早年生涯

阮福映原名阮福暖（），又名阮福种（），是阮福㫻与阮氏环的第三子。阮福㫻是阮福濶的次子。据阮朝的官方正史记载，1765年阮福濶逝世，因世子阮福昊已死，便遗命让阮福㫻继位。但权臣张福峦却篡改了遗诏，让年幼的第十六子阮福淳继位。不过，也有历史学家认为阮福㫻被确立为继承人可能是19世纪阮朝建立以后才出现的一种观点；阮福昊死后，阮福濶指定阮福淳继位，阮福昊的长子阮福旸为替补人选。而在后来的西山之乱中，阮福旸的声望远远超过了阮福淳，而此时阮福映在各位王子中只是个不起眼的小人物。

阮福濶逝世时，阮福映年仅四岁，同父亲阮福㫻一起被幽禁在宫中，不久父亲阮福㫻就死了。阮福淳年少贪玩，专权的张福峦又贪婪残暴，导致了百姓的不满。1771年，阮岳、阮侣、阮惠三兄弟发动西山起义，立即得到了南河各地的响应。1774年，北河的郑主郑森见南河大乱，派黄五福南下讨伐。阮福映随定王阮福淳南逃至嘉定（今胡志明市一带）。此时，阮福映被定王授予掌使的官职，统帅左翊军。阮朝史料称，他虽然年少，但多出奇谋，深得诸将的尊敬，也得到了定王的器重。

1777年，西山朝君主阮岳派遣阮惠、阮侣攻打嘉定，年仅十五岁的阮福映被太上王阮福淳派往三埠（位于今前江省一带）募兵。不久，旧阮的新政王阮福旸同众多宗室大臣一起，在龙湖营（今永隆省一带）被西山军俘虏杀害。太上王逃往橙江（位于今前江省一带），阮福映率东山军将其迎接到芹苴。随后，太上王在龙川（今金瓯省）被阮惠俘虏并杀害。许多阮氏王子遇害，但阮福映幸免于难。

他逃到了沥架，被天主教牧师保罗·谊（Paul Nghi，Phaolô Hồ Văn Nghị）藏了起来。此后他逃到了河仙镇，在那里，他遇上了法国巴黎外方传教会的百多禄主教。得到保罗·谊的情报后，百多禄避开了在柬埔寨的西山军，前来帮助阮福映。阮福映许诺在夺回政权之后将会给予基督教自由传播的权力，因此百多禄动心了。他们一起进入森林逃避西山军追捕，此后二人一起逃亡到了土朱屿。

重回南河

嘉定一带的争夺战

阮惠、阮侣在攻灭旧阮政权之后，留总督凋镇守嘉定，自己则率军回到归仁。在得知西山军主力撤离嘉定之后，阮福映率其支持者自土朱屿回到龙川，起兵反抗西山朝。阮文仁、杨公澄将阮福映迎至沙沥（今同塔省沙沥市）。旧阮残馀势力纷纷举兵响应，杜清仁、黎文匀、阮文弘、宋福匡、宋福梁等将驱逐了总督凋，夺回了嘉定城。旧阮势力得以复辟，阮福映被众将推举为「大元帅摄国政」，当时年仅十七岁。

阮岳派军队前来攻打，被杜清仁率东山军击退。阮福映趁机派遣黎文匀发起反攻，夺取了平顺、延庆两府。在内政方面，阮福映重新设置了阮主时代的府僚，并制定税例抽税养兵，制造战船积极备战。在百多禄的帮助下，旧阮制造了大量新式武器，包括了新式武器手榴弹。百多禄还从葡萄牙购买了三艘西式军舰，聘请法国探险家幔槐（Manuel）为船长。旧阮势力再次强大，嘉定城附近的藩安、边和、定祥、永清、河仙镇都被旧阮收复，西山军屡次征讨都未能成功。日趋强大的旧阮甚至派遣介入了柬埔寨的内战。1779年，亲暹罗的安农二世（匿螉嫩）登上了柬埔寨王位。阮福映派杜清仁、胡文璘前去征讨，杀死安农，拥立亲越南的安英（匿螉印）登位，并留胡文璘守柬埔寨。

1780年阴历正月，阮福映正式称王，人称「阮王」（）。阮福映使用后黎朝的景兴年号，并恢复使用广南阮主的「大越国阮主永镇之宝」。但次年因杜清仁功高震主，阮福映命宋福添杀之；其下属的东山军纷纷背叛，旧阮陷入混乱之中。暹罗国王郑昭得知之后，趁机派遣通銮·扎克里（即后来的拉玛一世）、素拉西（即后来的二王素拉辛哈那）二兄弟攻打柬埔寨，阮福映遣阮有瑞前去支援。由于当时郑昭猜忌通銮，将通銮二兄弟的家小监禁；通銮二人得知后，便与阮有瑞达成和解，相约为兄弟。恰巧此时暹罗发生兵变，通銮·扎克里率军回国平乱，寻获郑昭诛杀之，并杀死发动政变的披耶·讪。随后，昭披耶·扎克里继位为新的暹罗国王——拉玛一世，以素拉西为第二王，通因为第三王。旧阮因而巩固了其在柬埔寨的霸权地位。

1782年阴历三月，阮岳在归仁得知旧阮内乱，与阮惠亲率水步兵三千、战船若干南下攻打嘉定。旧阮军与西山军在嘉定附近的交战。虽然旧阮军有三艘军舰的参战，但西山军的水军趁顺风到来之际猛冲旧阮水军。由于指挥上的失误，旧阮军队大败，幔槐阵亡，并损失了一艘军舰。这场战役中旧阮军队遭到毁灭性打击，阮福映被迫弃嘉定城，逃往富国岛。西山军攻取嘉定，留杜闲蛰守城，阮岳、阮惠率主力部队回到归仁。

再失王位，流亡暹罗

阮福映败逃富国岛，但其支持者依然抗击西山朝。就在阮岳、阮惠班师回朝之后，同年的阴历十月，富安府的朱文接率军起兵，阮福映的弟弟阮福旻也举兵响应。朱文接收复了嘉定，迎阮福映回城。但次年阴历二月西山朝又派阮惠、阮侣前来攻打。西山军在四岐江旁背水一战，旧阮大败，阮福旻阵亡，重要将领杨公澄、阮黄德被俘。阮福映不得已，再次逃往富国岛。这次阮惠希望一举歼灭阮福映势力，于是在休整兵马之后，于六月攻打富国岛。阮福映不敌，败走昆仑岛。阮惠再攻昆仑岛，由于西山军许多战船遭遇风暴而倾覆，阮惠被迫罢兵。阮福映经古骨屿（今阁骨岛）逃回富国岛。

身处富国岛的阮福映残部没有粮草，只能采草芋充饥。当时百多禄正在暹罗的尖竹汶传教，阮福映派人前去商议，决定派遣范文仁、阮文廉护送嫡长子阮福景，随百多禄前往法国求救。但因风不顺，百多禄一行始终未能出发。另一方面，阮福映派朱文接前往暹罗求救。1783年底，朱文接到达暹罗首都曼谷，觐见了暹罗国王拉玛一世。拉玛一世派大将知蚩多率水军前去接应阮福映。暹罗水军于次年阴历二月到达河仙镇，与阮福映商讨共抗西山朝的事宜。阮福映随暹罗军队来到曼谷，在那里招募逃往到暹罗的旧部，伺机返回越南。拉玛一世以非常隆重的礼节欢迎阮福映，并答应将出兵助其归国。

1784年（西山朝泰德七年），阮福映率旧部朱文接、阮文诚、鄚子泩、阮文威等攻打嘉定。暹罗国王拉玛一世先派六昆、沙苑会同暹罗任命的柬埔寨摄政昭披耶·阿派普贝至柬埔寨，由此进攻嘉定；七月后又派大将昭曾、昭霜率士兵二万、战船三百艘，从曼谷出发，渡海攻打嘉定。

暹罗军势如劈竹，连破沥架（今坚江省迪石市）、巴色（今朔庄省朔庄市）、茶温（今永隆省茶温县）、斌沏（在今永隆省）、沙沥（今同塔省沙沥市社）等地。黎文匀据茶津（今前江省）响应阮福映。旧阮方面的统帅朱文接在攻打斌沏的时候阵亡，阮福映任命黎文匀接替其统帅之职。西山军守将张文多不敌，被迫撤离了嘉定，派邓文真向归仁求救。阮岳得悉后，便派阮惠前去防御，驻军于是美湫。

暹罗军队在嘉定一带烧杀抢劫，掠夺了大量金银财宝和奴隶送回暹罗。暹罗人对阮福映表现得非常轻慢。阮福映也看到了暹罗出兵相助事实上是想乘机占领嘉定之地，对此非常失望，认为暹罗必败，事先派遣鄚子泩来到镇江（今芹苴市、后江省一带）组织战船，为自己留下后路。

阮惠派兵数次攻打暹罗水寨，然后撤退。此后，又遣人赠送给昭曾丰厚的礼物，请求不要干涉西山朝与旧阮的内战。昭曾高兴地收下了礼物，这使暹罗更加轻敌，也造成了暹罗与旧阮双方互相猜疑。阮惠便使用诱敌深入之计，在沥涔、吹蔑（亦作蔑）一带设伏引诱暹罗、旧阮联军到来，大破之。这场战役发生在1785年的阴历四月，被称为沥涔吹蔑之战。昭曾率领暹罗军队夺路而逃，在昭披耶·阿派普贝（昭锤卞）的接应下经柬埔寨逃回暹罗，全军只有两千至三千人幸存。旧阮军队几乎全军覆没，阮文威阵亡，阮福映仅率亲信数人逃到镇江，由鄚子泩接应逃入暹罗，并遣人将国母阮氏环等家眷接至暹罗。阮惠则率军回到归仁，留邓文真守嘉定之地。后来嘉定成为西山朝东定王阮侣的封地。

寓居暹罗，向法国求救

阮福映逃至曼谷之后，仍有不少旧阮的支持者抗拒西山朝，但皆不是西山朝对手。后来旧阮将领阮黄德、黎文匀等人得知阮福映出奔暹罗之事，陆续前去投奔。拉玛一世安置这些越南人于曼谷城外的平原，令其自成一个村落。这个村落当时被称为「龙邱」（），今日的泰国人称之为「嘉隆村」。阮福映及其部众在这个村落里耕种，仍怀有东山再起之志。

拉玛一世把阮福映安置在曼谷郊外是因为看到阮福映尚有一定实力，本意是希望藉助阮福映的力量为己所用。而阮福映对此也心知肚明，因此积极参与暹罗的军事行动。阮福映在1785年的缅暹战争中，派遣黎文匀、阮文诚等人参战；此后又帮助暹罗击退马来海盗的骚扰。旧阮遗臣在对缅甸的战斗中作战英勇，拉玛一世大喜，厚赏之。阮福映便利用这些资金建造战船，准备伺机复国。

而在另一方面，阮福映迫切地需要得到法国的支持。在阮福映的一再敦促下，百多禄于1785年携其长子阮福景出发，并带有阮福映致法国国王路易十六的书信。同时被带去的还有阮福映的玉玺，这表明百多禄被阮福映委任为全权使者。为了能够在越南自由传教，百多禄尽其全力帮助阮福映复国。在临行前，百多禄派遣西班牙籍多明我会传教士耶妬悲、麻怒（Manuel）前去马尼拉，试图向菲律宾的西班牙殖民政府寻求援助，但遭西山军扣留并杀害。

1785年2月，百多禄一行到达法属印度的首府本地治里。但百多禄随即发现法国对越南并不感兴趣，因此派人向葡属澳门的议院求助。1786年，葡萄牙使者来到曼谷，与阮福映签订了同盟条约，答应为阮福映提供了56艘西洋军舰。翌年葡萄牙人安尊磊（António）自葡属印度的首府果阿来到曼谷，为阮福映带来了西式士兵和军舰。拉玛一世得知此事后非常不满，阮福映为了不使拉玛一世猜疑，被迫谢绝了葡萄牙人的援助。然而此次事件之后，阮福映不再受到暹罗人的信任。

1786年6月，百多禄一行从本地治里出发前往法国。1787年2月，百多禄一行到达巴黎，并与法国国王路易十六、海军大臣卡斯特里侯爵、外交大臣蒙莫兰伯爵会面。11月21日，双方签订《法越凡尔赛条约》。法国承诺派遣四艘军舰、1900名士兵前去支援阮福映；阮福映则愿意割让沱㶞（今岘港）、昆仑岛给法国，并给予法国人贸易特权。同年12月，百多禄一行乘坐Dryade号军舰离开法国，前往本地治里，准备借道本地治里归国。但27日行至本地治里的时候，却得知法国本土发生了极为严重的财政危机，政府濒临破产。法属印度总督伯爵以此为由拒绝给予援助。百多禄便通过自己的关系，招募了一些法国军官并购买一些法国武器、弹药和军舰。

与此同时，越南的旧阮支持者寄信给阮福映，告知了西山朝发生了内乱、阮惠与阮岳之间发生了军事冲突之事。同时，阮福映也得知镇守嘉定之地的都督邓文真已率主力部队前往归仁的消息。1787年阴历七月，阮福映留下书信辞别了拉玛一世，决定率部悄悄离开曼谷。这些越南避难者计划离开，被附近的人探知，告诉了披耶·拍康（พระยาพระคลัง，）。披耶·拍康将其报告给了拉玛一世和二王玛哈·素拉辛哈那。素拉辛哈那极为愤怒，亲自追赶他们。黎明时分，素拉辛哈那看见了在海湾口的船只。阮福映认为被抓获一定性命难保，做了自杀的准备，但被身边的人阻止。最终这些越南人成功逃脱。阮福映至富国岛，被流亡越南的天地会首领何喜文迎至龙川（今金瓯省）。西山朝将领阮文张率军300人、战船十五艘前来投奔。阮文仁等人也率旧部响应。镇守嘉定的东定王阮侣大为恐惧，留太保范文参守嘉定，自己则退往镇边（今同奈、平福、巴地头顿省一带）。阮福映伪造了一封阮岳写给阮侣的书信，声称范文参是内应，并故意将书信投递至范文参处。范文参率军以白旗先行，前往镇边，欲面白其冤。但阮侣见到白旗以后，误以为范文参已投降，惊恐之下弃城逃往归仁。范文参退守嘉定，阮福映围攻，一度不能胜并损失甚重；后来武性率部前来投奔，阮福映势力才得以恢复。1788年阴历七月，阮福映破范文参部，重新占领嘉定；翌年包围范文参部于巴忒，迫其投降。至此阮福映重新在嘉定站稳了脚跟。

巩固南方领地

阮福映在夺取嘉定之后，派阮文闲出使暹罗告捷，并对暹罗此前的帮助表示感谢。阮福映在嘉定整顿内政，禁止赌博和巫术，同时重新划分了行政区域，制定了一系列法律，整顿税收和农耕。阮福映推行「寓兵于农」的政策，任命郑怀德、黎光定、吴从周、黄明庆等十二人为田畯官，劝课农桑、开垦荒地，徵不愿务农者为兵。此外阮福映积极发展对外贸易，购买国外的金属以制造兵器；同时酌情降低关税，使得不少外国商船愿意来到嘉定经商。经过了一年多的休养生息，旧阮的势力逐渐强大。

1789年7月14日，百多禄与阮福景乘坐法国军舰Méduse号，携带法式枪支弹药返回嘉定。随行的还有法国海军军官让-巴蒂斯特·沙依诺、戴福桑、让-马里·达约等人。阮福映任命这些人为军官，大规模铸造西式兵器、军舰，旧阮的实力又一次得到壮大。根据西方史料的记载，法国Dryade号军官奥利维耶·德·皮曼纽尔叛逃到旧阮，为阮福映训练步兵和炮兵，将西方先进的步兵思想带到越南；而原为法国海军军官的达约、沙依诺则负责训练海军。至1790年，旧阮的陆军中已有五万名穿英国式制服、行欧洲式军礼、装备有西式先进武器并掌握西式战争技术的越南士兵；到了1792年时，旧阮海军已拥有两艘欧式军舰和十五艘护卫舰。至此，旧阮无论陆军还是海军的实力都已经比西山军强大，拥有绝对的优势。

阮福映不仅从欧洲引进了先进武器和训练方式，还按照西方的方法建造军事堡垒。1790年，德·皮曼纽尔与西奥多·勒布朗在嘉定建立了第一个西式城堡——八卦城（又称）。

全面北伐

1790年阴历四月，在发展有一定实力之后，阮福映派遣掌前军黎文匀军五千人攻打平顺府。旧阮军队以武性、阮文诚为先锋，轻而易举地攻克了平顺。但是由于黎文匀与武性的不和，西山军趁机反攻，夺回了平顺府，黎文匀被围困在潘里。阮文诚率军援救才击退了西山军。黎文匀因此服毒自杀。

对于日渐强大的旧阮，归仁朝廷的阮岳联合华南海盗，组织了一支舰队，停泊于施耐港，准备伺机南下征讨。阮福映得知后决定先发制人，1792年阴历三月，趁著季风到来之际，阮福映派阮文张、阮文诚、达约、瓦尼埃率水军从芹蒢海口（今胡志明市芹蒢县）出发，突袭并焚毁了西山朝归仁朝廷辖下施耐海口的水寨，全身而退。这场战斗中，由于西山军的战船壅塞于港口，遭到旧阮毁灭性打击，整支舰队只有9艘战船幸存。身处凤凰中都（位于今乂安省境内）的阮惠已得重病，得知阮福映势力日渐强大后病情恶化，不久逝世，其年仅十岁的长子阮光缵继位。

从1792年起至1799年期间，西山朝和旧阮的海军经常利用季风的改向而对对方的领地发动进攻。旧阮海军往往在夏季刮西南风的时候对西山朝发起进攻；而冬季到来之时，西山朝海军便利用东北风到来之际进攻旧阮。由于当时的西山朝政治混乱民不聊生，故而每当夏天来临的时候，西山朝辖下的百姓都盼望著东南季风的到来。

1793年阴历三月，阮福映册立长子阮福景为东宫，封元帅之职，镇守嘉定。遣尊室会、阮黄德、阮文诚率步兵北伐，攻取了平顺府。阮福映则与阮文张、武性率水军攻打沿海一带。五月，阮福映的水军先后攻取了延庆、平康、富安三府。旧阮在延庆府建立西式城堡——延庆城，以之为重镇。随后旧阮的水陆两军会合，夹攻归仁。阮福映率水军来到施耐海口，西山朝归仁朝廷的皇太子阮文宝领兵迎战，遭到旧阮的夹击大败。在这场战斗中，旧阮军队第一次使用了西方的先进武器——炸弹。

归仁朝廷君主阮岳向富春朝廷求救，阮光缵遣范公兴、阮文训、黎忠、吴文楚等人率17000名步兵和80名象兵、邓文真率30馀艘战船前去救援。阮福映不敌，经延庆回到嘉定，留阮文诚守延庆府、阮黄德守平顺府。鉴于延庆的地势重要，十一月又遣百多禄、范文仁、宋福溪，随阮福景前去镇守延庆城堡。

与此同时，西山朝富春朝廷兼并了归仁朝廷的领地，将阮文宝降为孝公。西山朝自此在军事上开始转入攻势。1794年阴历三月，西山朝派遣阮文兴攻打富安府、陈光耀攻打延庆府。阮福景、百多禄等人据守延庆城堡，抵抗在数量上具有相当大优势的西山军，并向嘉定求援。阮福映率大军救援，击退了西山军。阮福映将阮福景等人调回嘉定，换武性镇守延庆。翌年，武性再次成功抵挡了西山军的进攻。

1795年，西山朝发生内乱，裴得宣、吴文楚等重臣被杀，陈光耀被罢去兵权。西山朝的将领互相猜忌残杀，导致西山朝的实力被大大削弱。阮福映趁机发展兵备，并于1797年亲征归仁。途中突然临时改变了策略，攻打沱㶞（今岘港）。华南海盗首领陈添保派属下阮文伍截击，旧阮军队在激战之后被迫撤退。这次行动并不成功，因此阮福映在翌年派阮文瑞出使暹罗，请求暹罗出兵骚扰顺化、乂安边境一带；另一方面，派吴仁静出使清朝，希望牵制西山朝，同时探寻黎昭统帝的消息。而华南海盗则受西山朝的雇佣，骚扰旧阮辖下的沿岸，1797年阴历七月，陈添保曾率海盗大举入侵平康、延庆等府的沿海港口；但翌年遭到旧阮的击败，被迫离开这些地方。

1798年，久已不满的孝公阮文宝据归仁城叛乱，遣使通好于旧阮。阮福映派阮文诚前去接应，但兵未至阮文宝便被西山朝擒杀。这就是历史上的小朝之变。这场叛乱发生之后，多疑的阮光缵听信谗言，杀死了黎忠、阮文训等人，导致了黎质等人的背叛，西山朝文臣武将也都离心离德。见此机会，阮福映于次年大举北伐。西山朝派陈光耀和武文勇率陆军支援，水军则由被封为统兵的华南海盗首领樊文才率领。武文勇部在石津与旧阮的阮文诚部相遇，安营对峙；夜间恰巧有一只麋鹿西山军兵营前经过，有士兵惊呼，西山军以讹传讹，误以为旧阮的同狔兵偷袭，不战而溃。旧阮将领宋福梁击败了华南海盗，并与阮福映大军合兵，合力将沿海的华南海盗巢穴逐一捣毁。归仁城自此成为一座孤城，守将黎文清被迫献城投降。阮福映将归仁城改名为平定城，留武性、吴从周守城。1799年，阮福映派阮文瑞、刘福祥出使暹罗，希望调遣柬埔寨和万象之兵攻打西山朝，得到了暹罗王拉玛一世同意。随后，柬埔寨摄政召华塔拉哈 (波)派兵五千人前往乂安支援阮福映。

1800年阴历正月，西山朝派遣陈光耀、武文勇再度南下，试图夺回平定城。华南海盗为西山军提供了一百馀艘战船。由于双方兵力悬殊，西山朝大军包围平定城，采取围而不攻的策略，欲迫使武性投降。阮福映亲自率领八万水军，分乘1200艘战船（包括4艘欧式军舰、40艘大型战船和300多艘大划艇）北上救援。阮福映派武彝巍、黎文悦击退了驻守施耐海口的西山军武文勇部，又遣阮文张粉碎了华南海盗劫夺后勤物资的图谋，乘胜攻取了广南、广义两府。阮福映派阮文瑞、刘福祥二人前往联络万象。刘福祥率阮军从万象攻打乂安府，万象王因塔翁（昭印）派兵四千馀人协助。北河的豪强纷纷举兵支持旧阮。但是，旧阮军队始终无法冲破西山军对归仁的包围圈，因此阮福映令武性弃城逃出。武性拒绝了，并建议阮福映攻打西山朝首都富春（今顺化）。阮福映最终接受了武性的建议。

1801年五月，阮福映兵至思容海口，击败阮文治所率的西山军。旧阮乘胜追击，直入渜海口（今顺安海口）。阮光缵亲率西山军抵抗，根据参战的让-巴蒂斯特·沙依诺描述，这是旧阮与西山朝之间爆发的最为惨烈的一战，战场上尸横遍野。西山军大败溃散，支持西山朝的华南海盗也遭到旧阮军队的沉重打击，重要海盗首领东海王莫观扶以及统兵梁文庚、樊文才被旧阮俘虏。阮光缵率太宰阮光绍、元帅阮光卿、大司马阮文赐等人，经洞海垒渡过江，逃往北河，印章玺绶全被旧阮军缴获。皇后黎氏玉评也被旧阮俘虏。阮福映将黎氏玉评纳为昭媛。

1801年阴历五月初三，阮福映进入富春城，张榜安民。随后派阮文张、黎质率水步两军追击阮光缵，未能追及。阮光缵逃到北河，被阮光垂迎至升龙（今河内市），改元宝兴。而陈光耀、武文勇得知富春被攻陷后，欲回军救援，但被黎文悦部扼守道路，于是奋力攻破了平定城，武性、吴从周自杀。陈光耀、武文勇以平定城为据点，攻打周边的旧阮城镇，皆无功。

1802年阴历正月，阮光缵在北河站稳脚跟之后，纠集北河的西山军，决定同旧阮发动最后一搏。与此同时，华南海盗首领郑七原已离开越南回到广东，在陈添保的劝说之下，率属下分乘200艘战船前往北河，表示效忠于西山朝。郑七抵达升龙后，被阮光缵封为大司马。但旋即陈添保认定西山朝败局已定，弃官逃往中国，向清廷投降。得到郑七的支持之后，阮光缵随即亲率大军三万南下，来到江，派郑七守日丽海口（日丽江入海口）。旧阮将领阮文张、邓陈常不敌，退往洞海（今广平省洞海市）。阮福映闻报，亲自率大军北上，遣范文仁、邓陈常守陆路，阮文张守水路。阮光缵派阮光垂围攻镇宁垒（又名洞海垒、日丽垒，位于今广平省），久攻不克；阮文张则在此期间突袭日丽海口，大破郑七率领的华南海盗。围攻镇宁垒的西山军惊恐之下溃散，阮光缵逃回升龙。身处平定城的陈光耀、武文勇，得知阮光缵战败后，率军弃城北上欲与之会合，但途中被旧阮击败并俘虏。

灭亡西山朝

嘉隆元年五月初二日（1802年6月1日），阮福映宣布停止使用后黎朝的年号景兴；改用新年号「嘉隆」。自此越南历史上最后一个封建王朝——阮朝自此诞生。势力日薄西山的阮光缵还希望藉助清朝的力量对抗旧阮，派遣阮登为使者，前往清朝求援。阮福映则于此时派遣郑怀德、吴仁静出使清朝，献上缴获的西山朝印绶，并将被俘虏的海盗首领莫观扶、梁文庚、樊文才三人移交清廷。两广总督吉庆审问了三人，得知西山朝一直支持华南海盗的事实，将此呈报清廷。嘉庆帝闻报后勃然大怒，下令驱逐西山朝使者，并命令吉庆将莫观扶、梁文庚、樊文才三人按大逆罪淩迟处死。

随后阮福映亲率大军北伐，清化督镇阮光盘献城投降。阮朝军队以摧枯拉朽之势向北推进，并迅速攻占升龙。阮光缵率宗室大臣逃跑，在凤眼县被农民俘虏，六月二十三日送至升龙。阮福映下令免除北河百姓一年的税收。阮福映任命阮文诚为北城总镇，管理当地事务；又在北城设置户曹、兵曹、刑曹职务，分别由阮文谦、邓陈常、范文登担任。阮福映还让后黎朝的后裔黎维����主持后黎朝皇室的祭祀，郑主的后裔郑楈主持郑主家族的祭祀，以安抚他们的支持者。

阴历七月，阮福映率军回到顺化，押解西山朝君臣至顺化太庙行献俘之礼。阮光缵及西山朝宗室阮光维、阮光绍、阮光盘等淩迟处死之后五象分尸；武将武文勇、陈光耀等枭首示众；文臣吴时任、潘辉益等则被押往北城河内，在河内文庙前施以鞭刑，然后释放。阮福映又声称「朕闻为九世而报仇」，下令将阮岳与阮惠的尸体从坟墓中掘出，捣弃其骸骨；并将阮岳、阮惠的头骨和阮惠夫妇的木主处以「幽禁外图家」的处罚。明命二年（1821年），改为「永禁监狱室」。

整顿内政

阮光缵在位期间政局动荡不安，政治腐败。因此阮福映在夺取政权之后，下令改革政治制度。1815年，阮福映参照中国的《大清律》，颁布了《嘉隆律书》。

地方行政

阮福映将越南全境分为北城、嘉定城以及朝廷直辖区域三个部分。其下又分为23镇4营。

• 北城下辖11镇：山南上镇（今兴安大部、河南、河内东部）、山南下镇（今南定、太平两省）、山西镇（今河内市西部和永福大部、富寿东部）、京北镇（今北江、北宁两省、河内北部）、海阳镇（今海防市和海阳省）、宣光镇（今宣光、河江两省）、兴化镇（今富寿西部、老街、山罗、和平、莱州、奠边等西北省份，包括今寮国部分领土）、高平镇（今高平省大部）、谅山镇（今谅山省）、太原镇（今太原、北𣴓两省）、安广镇（今广宁省）；

• 嘉定城下辖5镇：藩安镇（今胡志明市）、边和镇（今同奈、巴地头顿、平福一带）、永清镇（今永隆、安江一带）、定祥镇（今前江、坚江、槟椥、茶荣一带）、河仙镇（今金瓯省及富国岛一带以及柬埔寨西哈努克市）；

• 阮朝朝廷直辖7镇：清华镇（今清化省）、乂安镇（今乂安、河静两省）、广义镇（今广义省）、平定镇（今平定省）、富安镇（今富安省）、平和镇（今庆和省）、平顺镇（今平顺、宁顺两省）；

• 京畿直辖4营：直隶广德营（今承天顺化省）、广治营（今广治省）、广平营（今广平省）、广南营（今岘港市和广南省）；

其中，京畿由阮朝朝廷直接管理，北城和嘉定城分别设置总镇和副总镇（或称协镇）以管理事务。北城和嘉定城的总镇都是由立下赫赫战功的武将担任。各镇以留镇或镇守为长官，镇之下又细分为府、县、州，由知府、知县、知州为长官。

阮福映也意识到北城这片刚占领的领地形势错综复杂，既存在有支持后黎朝和郑主势力的馀党，也存在著据守山区、朝廷难以管理的土豪，而且这些势力依然强大。阮福映认为北城地区「民性骄顽」，难以统治，因此并没有遵循前代历朝定都河内的惯例，而是将都城选在了历代阮主的统治中心顺化。1803年，阮福映命黎质、范文仁、阮文谦，参照中国紫禁城的建筑风格，在富春城内修建顺化皇城，作为阮朝朝廷的行政中心。

对于北城存在的各种势力，阮福映决定任命他们为官。北城的11镇被分为内五镇和外六镇，内五镇由后黎朝旧臣管理，外六镇由地方土豪管理。这种委任地方势力为官的制度直到明命帝继位的时候才被废止。

阮福映在位期间，参照法国的沃邦式城堡的建筑风格，在越南全境又先后建立了9座城堡。这些城堡分别是北城辖下的，朝廷直辖地的顺化、、、、庆和、，以及嘉定城辖下的、河仙。德·皮曼纽尔和西奥多·勒布朗在战争结束之后离开了越南，越南工程师们参照他们建造八卦城和时用的建筑图纸，建造了这些城堡。阮福映认为国家刚刚步入安定时期，百姓容易受朝廷调遣；若再过数年，百姓便习惯于安逸生活，那时再徵调他们建造大型工程，就很容易引起百姓的不满。故而他在位期间大兴土木，建造了众多工程。他还积极修建官道、修建驿站、疏通河流、建立堤坝。

军事制度

阮福映灭西山朝之后，赏赐有功将士，允许年老体弱者卸甲归田。又赏赐并修建庙宇，祭祀阵亡将士。他制定了兵丁之法：广平至平顺各镇三丁抽一，边和以南各镇五丁抽一，河静以北、北城内镇七丁抽一，北城外镇十丁抽一。京畿一带设立亲兵、禁兵、精兵，统称三兵，以守卫顺化。各镇设立奇兵、募兵，分作三番轮流值班。阮朝设置五军都统府，其首领由皇帝的亲信担任。若要动用军队，则由五军都统率兵出征。

而在兵器上，阮朝军队使用的主要是剑槊、马刀以及铜制大炮，也有使用西洋的枪支鸟铳。阮朝在顺化设立三个射击场士兵每年进行一次射击演习。但阮朝朝廷对西洋枪支的使用非常苛刻，每队50人中只有5人拥有鸟铳，每人每年只允许使用六发子弹，超过数目者要赔偿。

阮福映非常重视海港的军事防备，在各港口都建立炮台，检查过往船只；又建造了巨大的船只以巡防海面。而对于活跃于南中国海沿岸的华南海盗，阮福映持严厉打击的态度。1802年，就在阮福映推翻西山朝后不久，阮朝官军便攻陷了华南海盗位于江坪（今中国广西壮族自治区东兴市江平镇）的大本营，将著名的海盗首领郑七俘虏并斩首。此后官军清剿华南海盗在越南沿海一带根据地，华南海盗势力遭受沉重打击，不得不离开越南，回到中国广东一带发展。

经济制度

在财政税收上，阮福映重新规定了丁税、田税的相关法律。阮朝将全国的田地分为三等，按田地质量的优劣来衡量田税徵收的多少。若地方遭遇自然灾害，或者国家徵用壮丁修路、挖河、建城等，则酌情减税。阮福映制定了丁簿、田簿制度，地方每隔五年对壮丁（18岁以上、59岁以下男性）、田地进行一次调查并编制成册。阮福映颁布法律，禁止了后黎朝时期盛行的买卖公田的行为，但准许在应急的时候租借公田使用三年；超过期限不还者要受到法律的惩罚。

阮福映还制定了商税和矿税，以及香、参、席、木、燕窝等税收。朝廷规定商税按照船舶的大小来徵收。

嘉隆帝在位时期，阮朝直辖领地、北城外镇、北城内镇所规定的税收标准不同，但都由朝廷制定；而嘉定城的税收标准则由嘉定总镇确定。

1803年，阮福映先后在顺化、河内、嘉定开设铸钱炉，铸造嘉隆通宝。1810年制造丈量土地的标准铜尺并颁发给地方；1813年，又制造平天衡发给各营各镇。

官僚制度、法律制度

1811年，阮福映下令废除后黎朝的《洪德律》，命阮文诚为总裁，主持编纂新的律书。阮文诚等人参照中国的《大清律》，编成《嘉隆律书》（当时称为《皇朝律例》）二十二卷，共计398条。1815年，阮福映将此律书颁行各地。

越南历史学家陈仲金认为《嘉隆律书》是在《大清律》上做些许修改之后颁行的。越共学者则认为，《嘉隆律书》宣扬妇女的三从四德和皇帝的绝对权力，「极其保守和顽固」，是「反动」而「退步」的。

在官僚制度上，阮朝沿用了后黎朝的六部制度，各部以尚书为长官，下设参知、侍郎、郎中、员外郎、主事等官。又设督察院以劝谏皇帝、弹劾大臣。

而对于宫中的事务，阮福映定下了皇帝生前不立皇后的规矩。宫中只设有皇妃和宫嫔，按等级分为一阶至九阶；皇帝驾崩之后，嗣君继位，才尊其母为皇太后。皇太后死后，追赠皇后的称号。

对于爵位，阮福映规定不得封异姓大臣为王爵。皇子虽可以封王，但不能拥有实权。

科举与学术

阮福映是通过暴力手段夺取政权的，因此阮福映手下的重臣多是武将出身。但阮福映意识到治理国家也需要文臣，因此在阮朝建立之后，阮福映恢复了被西山朝废除的科举制度，在全国各地建立文庙，在顺化设立国子监，推行儒学，教授四书五经。

阮福映也关注越南地理书籍和国史的编纂。《皇越一统舆地志》、《大南会典事例》等书便是奉阮福映之命编纂的。《大南实录》也开始编纂。阮福映在位期间，也是越南文学发展的时期，涌现出大量包括字喃文学在内的诗歌小说，《大南国史演歌》以及著名的《金云翘传》都是在这个时期问世的。

宗教政策

阮福映推崇儒家思想。而东宫阮福景在西方思想的熏陶下更倾向于基督教，这令阮福映很不满。因此，在阮福景生前，阮福映曾与他多次发生思想上的冲突，有时候阮福映甚至大发雷霆。但是，阮福映仍然遵守之前的诺言，允许西方传教士在越南自由传教。嘉隆年间，共有六名传教士来到越南活动，这些人来自法国或西班牙。当时北城辖境内共有三十万名基督徒，而嘉定城境内有六万名。但是阮福映竭力推崇儒家思想以限制基督教的传播。

此外，虽然宫中的后妃多信奉佛教，但阮福映在政策上对佛教也进行了限制，他颁布法律，禁止民间对祭祀神佛的活动大操大办。

外交政策

• 与法国的关系：百多禄试图让阮福映与西方国家接近并贸易，但随著1799年百多禄的死而以失败告终。法国皇帝拿破仑一世有徵服越南的野心，他希望将越南作为法国在远东的殖民地以抗衡英国在印度的霸权。但拿破仑忙于在欧洲打仗，无暇东顾，后来也随著拿破仑的被流放而不了了之。波旁王朝复辟之后，法国首相黎塞留公爵派Cybele号来到沱㶞港（今岘港），向阮朝朝廷赠送了一艘配备有52支枪的护卫舰作为礼物，还转交了法国国王路易十八的国书，希望阮福映践行他在《法越凡尔赛条约》中的承诺。但阮福映认为自己并没有得到法国的实际援助，故而拒绝了法国的要求，却其国书并且退回了法国的礼物。

• 与英国的关系：1804年，英国人约翰·罗伯茨（John Roberts）来到越南，要求在广南的茶山建立商馆。由于阮福映曾在马德拉斯和加尔各答从不列颠东印度公司那里购买武器，为了信守诺言，阮福映给予了英国一定贸易特权。但建立商馆的要求遭到拒绝，英国的礼物也被退回。1822年，明命帝终止了英国人的贸易特权。

• 与中国的关系：1803年，阮福映派遣郑怀德、黎光定出使清朝请封。阮福映取「安南」的「南」字、「越裳」的「越」字，请求清朝赐国号「南越」；但嘉庆帝将其改为「越南」，这就是今日越南国名的由来。嘉庆帝认为历史上「南越」之地较广，两广（广东与广西）皆在其内；阮福映全有安南，亦不过是交趾故地，故而将其二字顺序颠倒。不过，清朝回覆安南时称，以「越」字冠于「南」字之前，表示阮福映先继承越裳之地，而再开拓疆域于安南，不仅名称正大、字义吉祥，又能与两广的旧称「南越」相区别开来。次年，嘉庆帝派遣广西按察使齐布森出使越南，册封阮福映为越南国王，颁赐越南国王金印一枚。阮福映来到升隆（今河内）接受清朝的册封，随后遣黎伯品充如清正使，陈明义、阮登第充甲乙副使，前往清朝进贡并谢恩，双方约定三年一贡为惯例。1806年，阮福映正式举行登基大典，确定新国号「大越南国」。但原国号「大越」仍被使用，直至1839年被明命帝废止。

• 与暹罗的关系：阮福映即位前曾流亡暹罗，暹罗曾于1784年出兵越南，试图协助他复位，但失败。后来阮福映趁西山朝内乱之机回到越南，重新占据了嘉定，以此为基地进行北伐并最后统一全国。根据泰国《拉达那哥欣皇家编年史》记载，在阮福映称帝之前，曾先后六次向暹罗王拉玛一世进贡金银花，以表示臣服之意。在北伐西山朝的战争中，阮福映曾派人向暹罗请求调遣柬埔寨、万象的士兵，得到拉玛一世的同意。阮福映建立阮朝以后，不再向暹罗进贡金银花，但仍与暹罗互相派遣使者。1813年，阮朝曾与暹罗因柬埔寨问题而发生冲突，但在嘉隆年间双方总体上保持著友好往来的关系。

• 与柬埔寨的关系：1779年，阮福映将柬埔寨变为附庸国；但在1782年嘉定被阮惠攻陷之后，旧阮丧失对柬埔寨的控制。不久，柬埔寨发生内乱，国王安英（匿印）出奔暹罗。拉玛一世乘机将其扣留，并派昭披耶·阿派普贝监督柬埔寨内政。1796年安英逝世时，暹罗不准其子安赞二世（匿螉禛）归国继位。直到柬埔寨摄政召华塔拉哈 (波)去世后，方才册封安赞二世为王。安赞二世不满于暹罗的统治，在外交上游走于越南和暹罗之间。1807年弃暹罗向越南朝贡。这侵犯了暹罗的利益，1811年，暹罗暗中扶持安斯农（匿螉原）叛乱。安赞二世逃往嘉定城，向阮朝朝廷求救。1813年，阮福映遣黎文悦携安赞二世归国复位，并驻兵南荣（今金边）、卢淹（今干丹省勒维恩县）两城，将柬埔寨重新变为越南的附庸国。安斯农出奔暹罗，暹罗驻军于今马德望省一带，欲以该地区封安斯农为王。黎文悦作书谴责暹罗，暹罗与越南达成和解之后撤离了该地。在阮福映在位期间，越南与暹罗没有发生过正面的军事冲突，而柬埔寨则同时向越南和暹罗朝贡。

• 与琅勃拉邦的关系：琅勃拉邦王国（南掌）此前曾发生王位纠纷，故王之子曼古·拉加古曼（Ong Manhku Rajakoumane，温猛）与国王阿努鲁塔（𦵚乍）争夺王位。曼古获得清朝的承认和册封，进攻阿努鲁塔，战败后逃往兴化的昭晋州（今莱州省丰收县）投奔当地土司。1802年秋，曼古来升隆（今河内）朝见阮福映。阮福映认为天下初定，没有时间处置这件事情，让他回昭晋州。与此同时，阿努鲁塔遣使，请求从宁边州（今奠边府市）入贡。1809年，曼古又被北城臣送来顺化。阮福映将他送往谅山的镇南关（今中越边境友谊关），让清朝处置。清朝认为曼古不能自立，拒绝了他的王位请求并没收其敕印。此后，曼古客居昭晋州直至逝世。

• 与万象的关系：阮福映早在流亡暹罗期间就与万象王国（zh-hans:万象;zh-hant:万象;）国王因塔翁（昭印）相识。在北伐西山朝战争期间，万象曾出兵配合。阮朝建立的时候，因塔翁遣使入贡，阮福映命令将川圹（镇宁）之地隶属于万象。因塔翁去世后，暹罗立因塔翁之弟昭阿努（阿弩）为万象王。阮福映派该奇阮文蕴、翰林黎文富前往万象赐赙。川圹发生王位继承权的斗争，在阮朝与万象的支持下，昭内登上了川圹王位。

诛杀功臣

根据史料记载，阮福映在晚年性格多疑，常对大臣起猜忌之心。而一些朝中大臣之间有互有嫌隙，因此邓陈常、阮文诚等一些功臣遭到杀害。

邓陈常在阮福映还在嘉定期间便前去投奔，随其颠沛流离，后因战功逐渐升迁，任北城兵曹，后又任兵部尚书。兵部尚书任内，因将郑主部将黄五福列为福神被人告发而失势。黎质与其有仇，1813年，趁机告发其在北城兵曹任内的不法之事，阮福映下令将邓陈常罢官下狱。邓陈常甚为不满，在狱中作《韩王孙赋》一首，自比为汉朝的韩信。阮福映大怒，欲杀邓陈常，皇子阮福胆力救不能免。阮福映令邓陈常自杀，但邓陈常不从，遂被绞死。

阮文诚也是阮福映的旧臣，此人文武双全，在征讨西山朝的战斗中立下赫赫战功。阮朝建立后担任北城总镇，之后回京任中军之职，《嘉隆律书》也是此人主持编纂的。但他与另一重臣黎文悦有仇，阮文诚曾派人暗杀黎文悦，但未成功。1817年，阮文诚之子阮文诠写了一首颇为自大的诗，黎文悦便告发阮文诠有谋反之心。于是阮文诚被逮捕入狱。阮福映命黎文悦审问阮文诠，黎文悦强迫阮文诠认罪。于是阮福映迫使阮文诚饮毒药自尽，其子阮文诠处斩。

晚年及逝世

在阮福映建立阮朝之后，仍有法国人沙依诺（阮文胜）、瓦尼埃（阮文震）、德斯皮奥以及巴里西等人在朝中担任高官。阮福映给予他们特殊的待遇，赐予他们50名卫兵，准许上朝时免行跪拜之礼。虽然阮福映对他们礼遇有加，但他们都感到郁郁不得志。阮福映逝世后不久，沙依诺便向继任的明命帝提出辞官告假三年，返回了法国。此后法国籍官员也陆陆续续提出辞职，黯然归国。

1801年阮福景逝世后，虽然按照惯例应该由阮福景的长子阮福美堂担任皇嗣孙，但由于阮福景一系有强烈地亲西方和基督教倾向，且阮福美堂尚未成年，故而阮福映迟迟不立继承人。1815年，阮福映立推崇儒家思想的庶子阮福胆为皇太子，将阮福景一系的子孙排除在了皇位继承权之外。

虽然阮福映在夺取皇位的过程中受到西洋人的帮助，但他认为西洋人「非我族类，其心必异」，对西洋人存在有相当大的戒心。然而他也看到了阮福胆的内心具有强烈地排外和反基督教倾向，故而告诫阮福胆，要求他要尊重欧洲人特别是法国人，但不要给予他们任何优待，更不能把土地割给法国。

1820年2月1日（嘉隆己卯年腊月十七），阮福映病重，召皇太子阮福胆、诸皇子、诸公以及大臣黎文悦、范登兴入宫，宣布了遗诏，任命黎文悦、范登兴为辅政大臣。腊月十九，阮福映驾崩，在位18年，寿58岁。阴历正月初一，皇太子阮福胆改名阮福晈并正式继承皇位，是为明命帝。

阮福映死后庙号世祖（），諡号开天弘道立纪垂统神文圣武峻德隆功至仁大孝高皇帝（）。其遗体被合葬于其原配宋氏兰之陵寝，葬于宋氏兰坟丘的左侧，两陵寝统称天授陵。

形象

阮福映擅于使用鸟枪，发无不中。他也爱好读书尤其是史书，在位期间曾多次要求下诏让民间献书。

阮福映的性格直率而果断，文臣武将往往能在他面前直接表露出自己内心的想法。他不仅喜爱宫廷舞蹈等士大夫的爱好，也喜爱斗鸡、㗰剧等越南民间的爱好。在私下场合他会表现出平易近人。据说黎文悦曾在他面前开玩笑地就斗鸡问题发表长篇演说。

阮福映用人不重视出身，如：朱文接出身马商，黎文悦出生农民。他也不重视其种族，其部将有众多外国人，如：法国人沙依诺、瓦尼埃、达约、皮曼纽尔、戴福桑、勒布朗等人，高棉人阮文存，中国人何喜文、黄忠仝、张公引，还有暹罗人温利·马卢（Vinhly Malu，荣麻离）。投降的部将只要有才能也受重用。

阮福映也是个守信的人。他信守自己的诺言，允许传教士在越南自由传教，还给予英国人贸易特权，虽然他并不情愿这么做。他死后，明命帝便遵循其遗训废除了英国的贸易特权，后又发布禁教令。

而在当时的西方，阮福映则被宣传为基督教徒的庇护者，西方人认为他推动了基督教在越南的传播。而事实上阮福映偏向于儒家思想，在内心里对基督教比较抵制。

评价

• 西山朝君主阮惠把阮福映看作是西山朝的最大祸患。阮惠临终时，阮福映势力日渐强大，因此阮惠对西山朝的未来非常担忧。

• 法国传教士古拉尔（Guérard）认为：「嘉隆王用一切手段敲榨人民，不公正和横行霸道，使得人民比西山时期更加痛苦。赋税和劳役增加三倍。」

• 阮朝维新年间编纂的《国朝正编撮要》，对阮福映作如是评价：「帝中兴创业，功德兼隆，鸿厖以降未之有也。立国之始，营城郭，修陵寝，建郊庙、社稷，班爵制禄，开科取士，兴礼乐、学校，定法度、条律，存黎、郑之后，延功臣之世，郤西山之献，密暹罗之防，怀真腊，抚万象，威震殊方，仁覆小邦，规模葢宏远矣。」

• 越南历史学家陈仲金认为，阮福映是一位「具有才智的国君，聪明睿智，在长达25年的时间之内与西山相抗，经历了无数艰难险阻，但何时候也未曾灰心丧气，而仍一心一意思虑复国大业。」；陈仲金又评价阮福映「颇具创大业之美德，知人善任，使豪杰之士人人都忠心耿耿为之效忠命」，「因此他不仅恢复了旧业，而且还统一了山河，进行诸项改革，使当时的我国成为一个空前未有的强大国家」；但是对于阮福映晚年杀害功臣之事陈仲金也提出批评，认为他像汉高祖一样滥杀功臣。

• 越共对阮福映的评价非常差，认为他发动「反革命战争」，依靠外国势力镇压农民起义，建立了越南历史上最后一个而且是最「反动」的封建王朝。对于其即位之后的各项改革越共也都评价不佳，认为其最终目的都是「镇压人民的反抗」。

• 中国学者郭振铎、张笑梅认为，阮福映在世「既有过又有功」，但是「过大于功」。他藉法国之助镇压西山起义，「为法国进入越南并将越南变成法国殖民地奠定了基础」；他在位期间对外侵略柬埔寨，对内「专制独裁，压迫人民」，晚年又杀害功臣，因此其过匪小。而他的功劳在于「将动乱分裂的越南社会归于统一」，之后又施行一系列改革，「对越南封建社会发展起了一定推动作用」。

家庭

后宫

子女

包括未序齿的子女在内，阮福映有子19人，女18人。

注释

Early years

Born in Phú Xuân (modern-day Huế, central Vietnam) on 8 February 1762, he also had two other names in his childhood: Nguyễn Phúc Chủng (阮福种) and Nguyễn Phúc Noãn (阮福暖). Nguyễn Ánh was the third son of Nguyễn Phúc Luân and Nguyễn Thị Hoàn. Luan was the second son of Lord Nguyễn Phúc Khoát of southern Vietnam; the first son had already predeceased the incumbent Lord. There are differing accounts on which son was the designated successor. According to one theory, Luân was the designated heir, but a high-ranking mandarin named Trương Phúc Loan changed Khoat's will of succession on his deathbed, and installed Luan's younger brother Nguyễn Phúc Thuần, the sixteenth son, on the throne in 1765. Luan was jailed and died in the 1765, the same year as Thuan's installation. However, the historian Choi Byung Wook claims that the notion that Luân was the designated heir was based on fact but was propagated by 19th century Nguyễn dynasty historians after Nguyễn Ánh had taken the throne as Gia Long to establish the emperor's legitimacy. According to Choi, Lord Khoát had originally chosen the ninth son, who then died, leaving Loan to install Lord Thuần. At the time, the alternative was the eldest son of the ninth son, Nguyễn Phúc Dương, whom opposition groups later tried unsuccessfully to convince to join them as a figurehead to lend legitimacy. In 1775, Thuan was forced to share power with Dương by military leaders who supported the Nguyêns. At this time, Nguyễn Ánh was a minor member of the family and did not have any political support among court powerbrokers.

However, Thuan lost his position as lord of southern Vietnam and was killed, along with Duong, during the Tây Sơn rebellion led by the brothers Nguyễn Nhạc, Nguyễn Huệ and Nguyễn Lữ in 1777. Nguyễn Ánh was the most senior member of the ruling family to have survived the Tây Sơn victory, which pushed the Nguyễn from their heartland in central Vietnam, southwards towards Saigon and into the Mekong Delta region in the far south. This turn of events changed the nature of the Nguyễn power hierarchy; the family and the first leader Nguyễn Hoàng had originally come from Thanh Hoa Province in northern Vietnam, and this is where most of their senior military and civil leadership's heritage derived from, but as a result of the Tây Sơn's initial successes, much of this old power base was destroyed and Nguyễn Ánh had to rebuild his support network among southerners, who later became the core of the regime when the Nguyễn dynasty was established.

Nguyễn Ánh was sheltered by a Catholic priest Paul Nghi (Phaolô Hồ Văn Nghị) in Rạch Giá. Later, he fled to Hà Tiên on the southern coastal tip of Vietnam, where he met Pigneau de Behaine, a French priest who became his advisor and played a major part in his rise to power. Receiving information from Paul Nghi, Pigneau avoided the Tay Son army in Cambodia, and came back to assist Nguyễn Ánh. They hid in the forest to avoid the pursuit of Tay Son army. Together, they escaped to the island of Pulo Panjang in the Gulf of Siam. Pigneau hoped that by playing a substantial role in a Nguyễn Ánh victory, he would be in position to lever important concessions for the Catholic Church in Vietnam, helping its expansion in Southeast Asia.

In late 1777, the main part of the Tây Sơn army left Saigon to go north and attack the Trịnh lords, who ruled the other half of Vietnam. Nguyễn Ánh stealthily returned to the mainland, rejoining his supporters and reclaimed the city of Saigon. He was crucially aided by the efforts of Do Thanh Nhon, a senior Nguyễn Lord commander who had organized an army for him, which was supplemented by Cambodian mercenaries and Chinese pirates. The following year, Nhon expelled additional Tây Sơn troops from the surrounding province of Gia Dinh and inflicted heavy losses on the Tây Sơn naval fleet. Taking advantage of the more favorable situation, Nguyễn Ánh sent a diplomatic mission to Siam to propose a treaty of friendship. This potential pact, however, was derailed in 1779 when the Cambodians rose up against their pro-Siamese leader Ang Non II. Nguyễn Ánh sent Nhon to assist the revolt, which eventually saw Ang Non II defeated decisively and executed.

Nhon returned to Saigon with high honor and concentrated his efforts on improving the Nguyễn navy. In 1780, in an attempt to strengthen his political status, Nguyễn Ánh proclaimed himself Nguyễn vương (Nguyễn king or Nguyễn ruler in Vietnamese) with the support of Nhon's Dông Sơn Army. In 1781, Nguyễn Ánh sent further forces to prop up the Cambodian regime against Siamese armies who wanted to reassert their control. Shortly thereafter, Nguyễn Ánh had Nhon brutally murdered. The reason remains unclear, but it was postulated that he did so because Nhon's fame and military success was overshadowing him. At the time, Nhon had much, if not dominant power, behind the scenes. According to later Nguyễn dynasty chronicles, Nhon's powers included that of deciding who would receive the death penalty, and allocating budget expenditures. Nhon also refused to allocate money for royal spending. Nhon and his men were also reported to have acted in an abrasive and disrespectful manner to Nguyễn Ánh.

The Tây Sơn brothers reportedly broke out in celebration upon hearing of Nhon's execution, as Nhon was the Nguyễn officer whom they feared the most. Large parts of Nhon's supporters rebelled, weakening the Nguyễn army, and within a few months, the Tây Sơn had recaptured Saigon mainly on the back of naval barrages. Nguyễn Ánh was forced to flee to Ha Tien, and then onto the island of Phu Quoc. Meanwhile, some of his forces continued to resist in his absence. While the murder of Nhon weakened Nguyễn Ánh in the short term, as many southerners who were personally loyal to Nhon broke away and counter-attacked, it also allowed Nguyễn Ánh to gain autonomy and then take steps towards exerting direct control over the remaining local forces of the Dong Son who were willing to work with him. Nguyễn Ánh also benefited from the support of Chau Van Tiep, who had a power base in the central highlands between the strongholds of the Nguyễn and the Tây Sơn.

In October 1782, the tide shifted again, when forces led by Nguyễn Phúc Mân, Nguyễn Ánh's younger brother, and Chau Van Tiep drove the Tây Sơn out of Saigon. Nguyễn Ánh returned to Saigon, as did Pigneau The hold was tenuous, and a counterattack by the Tây Sơn in early 1783 saw a heavy defeat to the Nguyễn, with Nguyen Man killed in battle. Nguyễn Ánh again fled to Phu Quoc, but this time his hiding place was discovered. He managed to escape the pursuing Tây Sơn fleet to Koh-rong island in the Bay of Kompongsom. Again, his hideout was discovered and encircled by the rebel fleet. However, a typhoon hit the area, and he managed to break the naval siege and escape to another island amid the confusion. In early-1784, Nguyễn Ánh went to seek Siamese aid, which was forthcoming, but the extra 20,000 men failed to weaken the Tây Sơn's hold on power. This forced Nguyễn Ánh to become a refugee in Siam in 1785. To make matters worse, the Tây Sơn regularly raided the rice-growing areas of the south during the harvesting season, depriving the Nguyễn of their food supply. Nguyễn Ánh eventually came to the conclusion that using Siamese military aid would generate a backlash among the populace, due to prevailing Vietnamese hostility towards Siam.

Pigneau and French assistance

Deflated by his situation, Nguyễn Ánh asked Pigneau to appeal for French aid, and allowed Pigneau to take his son Nguyễn Phúc Cảnh with him as a sign of good faith. This came about after Nguyễn Ánh had considered enlisting English, Dutch, Portuguese and Spanish assistance. Pigneau advised against Nguyễn Ánh's original plan to seek Dutch aid from Batavia, fearing that the support of the Protestant Dutch would hinder the advancement of Catholicism. Pigneau left Vietnam in December, arriving in Pondicherry, India in February 1785 with Nguyễn Ánh's royal seal. Nguyễn Ánh had authorized him to make concessions to France in return for military assistance. The French administration in Pondicherry, led by acting governor Coutenceau des Algrains, was conservative in outlook and resolutely opposed intervention in southern Vietnam. To compound the already complex situation, Pigneau was denounced by Spanish Franciscans in the Vatican, and he sought to transfer his political mandate to Portuguese forces. The Portuguese had earlier offered Nguyễn Ánh 56 ships to use against the Tây Sơn.

In July 1786, after more than 12 months of fruitless lobbying in Pondicherry, Governor de Cossigny allowed Pigneau to travel back to France to directly ask the royal court for assistance. Arriving at the court of Louis XVI in Versailles in February 1787, Pigneau had difficulty in gathering support for a French expedition in support of Nguyễn Ánh. This was due to the parlous financial state of the country prior to the French Revolution. Pigneau was helped by Pierre Poivre, who had previously been involved in seeking French commercial interests in Vietnam. Pigneau told the court that if France invested in Nguyễn Ánh and acquired a few fortified positions on the Vietnamese coast in return, then they would have the capability to "dominate the seas of China and of the archipelago", and with it, control of Asian commerce. In November 1787, a treaty of alliance was concluded between France and Cochinchina, the European term for southern Vietnam, in Nguyễn Ánh's name. Pigneau signed the treaty as the "Royal Commissioner of France for Cochinchina". France promised four frigates, 1,650 fully equipped French soldiers and 250 Indian sepoys in return for the cession of Poulo-Condore (Côn Đảo) and Tourane (Da Nang), as well as tree trade to the exclusion of all other countries. However, the freedom to spread Christianity was not included. However, Pigneau found that Governor Thomas Conway of Pondicherry was unwilling to fulfill the agreement; Conway had been instructed by Paris to determine when to organize the aid, if at all. Pigneau was thus forced to use funds raised in France to enlist French volunteers and mercenaries. He also managed to procure several shipments of arms and munitions from Mauritius and Pondicherry.

Meanwhile, the Royal Court of Siam in Bangkok, under King Rama I, warmly welcomed Nguyễn Ánh. The Vietnamese refugees were allowed to build a small village between Samsen and Bangpho, and named it Long-kỳ (Thai: Lat Tonpho). Ánh had stayed in Siam with a contingent of troops until August 1787. His soldiers served in Siam's war against Bodawpaya of Burma (1785–86). On 18 December 1786, Nguyễn Ánh signed a treaty of alliance with the Portuguese in Bangkok. In the next year, António (An Tôn Lỗi), a Portuguese from Goa, came to Bangkok, brought Western soldiers and warships to Ánh. This disgusted the Siamese and Ánh had to refuse the aid from Portuguese. After this incident, Ánh was no longer trusted by the Siamese.

Having consolidated their hold on southern Vietnam, the Tây Sơn decided to move north to unify the country. However, the withdrawal of troops from the Gia Dinh garrison weakened their hold on the south. This was compounded by reports that Nguyễn Nhạc was being attacked near Qui Nhơn by his own brother Nguyễn Huệ, and that more Tây Sơn troops were being evacuated from Gia Dinh by their commander Dang Van Tran in order to aid Nguyễn Nhạc. Sensing Tây Sơn vulnerability in the south, Nguyễn Ánh assembled his forces at home and abroad in preparation for an immediate offensive.

Ánh secretly left Siam in the night, leaving a letter in his house, he decided to head for southern Vietnam by boat. As the Vietnamese refugees were preparing to leave, people nearby heard about it and reported it to Phraya Phrakhlang. Phraya Phrakhlang reported it to King Rama I and the Front Palace Maha Sura Singhanat. Sura Singhanat was extremely angry, he chased them personally. At dawn, Sura Singhanat saw Ánh's boat at the mouth of the bay. Finally, the Vietnamese escaped successfully. Ánh arrived at Hà Tiên then to Long Xuyên (Cà Mau), but he failed in his first attempt to recapture Gia Dinh, having failed to convince the local warlord in the Mekong Delta, Vo Tanh to join his assault. The following year, Nguyễn Ánh finally managed to persuade the warlord to join him but after having given his sister to the warlord as a concubine. He eventually succeeded in taking Mỹ Tho, made it the main staging point for his operations, and rebuilt his army. After a hard-fought battle, his soldiers captured Saigon on 7 September 1788. Eventually, Pigneau assembled four vessels to sail to Vietnam from Pondicherry, arriving in Saigon on 24 July 1789. The combined forces helped to consolidate Nguyễn Ánh's hold on southern Vietnam. The exact magnitude of foreign aid and the importance of their contribution to Gia Long's success is a point of dispute. Earlier scholars asserted that up to 400 Frenchmen enlisted, but more recent work has claimed that less than 100 soldiers were present, along with approximately a dozen officers.

Consolidation of Southern Annam

After more than a decade of conflict, Nguyễn Ánh had finally managed to gain control of Saigon for long enough to have time to start a permanent base in the area and prepare to build up for a decisive power struggle with the Tây Sơn. The area around Saigon, known as Gia Dinh, began to be referred to as its own region, because Nguyễn Ánh's presence was becoming entrenched, distinguishing and associating the area with a political base. Nguyễn Ánh's military was able to consolidate, and a civil service was reestablished. According to the historian Keith Taylor, this was the first time that the southern third of Vietnam was integrated "as a region capable of participating successfully in war and politics among Vietnamese speakers", which could "compete for ascendancy with all the other places inhabited by speakers of the Vietnamese language". A Council of High Officials consisting of military and civil officials was created in 1788, as was a tax collection system. In the same year, regulations were passed to force half the male population of Gia Dinh to serve as conscripts, and two years later, a system of military colonies was implemented to bolster the Nguyễn support base across all racial groups, including ethnic Khmers and Chinese.

The French officers enlisted by Pigneau helped to train Nguyễn Ánh's armed forces and introduced Western technological expertise to the war effort. The navy was trained by Jean-Marie Dayot, who supervised the construction of bronze-plated naval vessels. Olivier de Puymanel was responsible for training the army and the construction of fortifications. He introduced European infantry training, formations and tactics while also facilitating various methods of manufacturing and using European-style artillery, thereby making cannonry and projectiles a central part of the military. Pigneau and other missionaries acted as business agents for Nguyễn Ánh, purchasing munitions and other military matériel. Pigneau also served as an advisor and de facto foreign minister until his death in 1799. Upon Pigneau's death, Gia Long's funeral oration described the Frenchman as "the most illustrious foreigner ever to appear at the court of Cochinchina". Pigneau was buried in the presence of the crown prince, all mandarins of the court, the royal bodyguard of 12,000 men and 40,000 mourners.

Fortifications

Layout of the original citadel.

Following the recapture of Saigon, Nguyễn Ánh consolidated his power base and prepared the destruction of the Tây Sơn. His enemies had regularly raided the south and looted the annual rice harvests, so Nguyễn Ánh was keen to strengthen his defence. One of Nguyễn Ánh's first actions was to ask the French officers to design and supervise the construction of a modern European-style citadel in Saigon. The citadel was designed by Theodore Lebrun and de Puymanel, with 30,000 people mobilized for its construction in 1790. The townsfolk and the mandarins were punitively taxed for the work and the laborers were so over-worked that they revolted. When finished, the stone citadel had a perimeter measuring 4,176 meters in a Vauban model. The fortress was bordered on three sides by pre-existing waterways, bolstering its natural defensive capability. Following the construction of the citadel, the Tây Sơn never again attempted to sail down the Saigon River and try to recapture the city, its presence having endowed Nguyễn Ánh with a substantial psychological advantage over his opponents. Nguyễn Ánh took a keen personal interest in fortifications, ordering his French advisors to travel home and bring back books with the latest scientific and technical studies on the subject. The Nguyễn royal palace was built inside the citadel.

Agricultural reform and economic growth

With the southern region secured, Nguyễn Ánh turned his attention to agricultural reforms. Due to Tây Sơn naval raids on the rice crop via inland waterways, the area suffered chronic rice shortages. Although the land was extremely fertile, the region was agriculturally underexploited, having been occupied by Vietnamese settlers only relatively recently. Furthermore, agricultural activities had also been significantly curtailed during the extended warfare with the Tây Sơn. Nguyễn Ánh's agricultural reforms were based around extending to the south a traditional form of agrarian expansion, the đồn điền, which roughly translates as "military settlement" or "military holding", the emphasis being on the military origin of this form of colonization. These were first used during the 15th-century reign of Lê Thánh Tông in the southward expansion of Vietnam. The central government supplied military units with agricultural tools and grain for nourishment and planting. The soldiers were then assigned land to defend, clear and cultivate, and had to pay some of their harvest as tax. In the past, a military presence was required because the land had been seized from the conquered indigenous population. Under Nguyễn Ánh's rule, pacification was not usually needed but the basic model remained intact. Settlers were granted fallow land, given agricultural equipment, work animals, and grain. After several years, they were required to pay grain tax. The program greatly reduced the amount of idle, uncultivated land. Large surpluses of grain, taxable by the state, soon resulted.

By 1800, the increased agricultural productivity had allowed Nguyễn Ánh to support a sizeable army of more than 30,000 soldiers and a navy of more than 1,200 vessels. The surplus from the state granary was sold to European and Asian traders to facilitate the importation of raw materials for military purposes, in particular iron, bronze, and sulfur. The government also purchased caster sugar from local farmers and traded it for weapons from European manufacturers. The food surplus allowed Nguyễn Ánh to engage in welfare initiatives that improved morale and loyalty among his subjects, thereby increasing his support base. The surplus grain was deposited in granaries built along the northward route out of Saigon, following the advance of the Nguyễn army into Tây Sơn territory. This allowed his troops to be fed from southern supplies, rather than eating from the areas that he was attempting to conquer or win over. Newly acquired regions were given tax exemptions, and surrendered Tây Sơn mandarins were appointed to equivalent positions with the same salaries in the Nguyễn administration.

Naval buildup

Nguyễn Ánh used his new Chu Su Naval workshop to improve his inferior navy, which was much smaller than the Tây Sơn fleet and hitherto unable to prevent their rice raids. Nguyễn Ánh had first attempted to acquire modern naval vessels in 1781, when on the advice of Pigneau, he had chartered Portuguese vessels of European design, complete with crew and artillery. This initial experience proved to be disastrous. For reasons that remain unclear, two of the vessels fled in the midst of the battle against the Tây Sơn, while angry Vietnamese soldiers killed the third crew. In 1789, Pigneau returned to Vietnam from Pondicherry with two vessels, which stayed in the Nguyễn service long-term. Over time, Vietnamese sailors replaced the original French and Indian crew under the command of French officers. These vessels became the foundation for an expanded military and merchant Nguyen naval force, with Nguyễn Ánh chartering and purchasing more European vessels to reinforce Vietnamese-built ships. However, traditional Vietnamese-style galleys and small sailing ships remained the mainstay of the fleet. By 1794, two European vessels were operating together with 200 Vietnamese boats against the Tây Sơn near Qui Nhơn. In 1799, a British trader by the name of Berry reported that the Nguyễn fleet had departed Saigon along the Saigon River with 100 galleys, 40 junks, 200 smaller boats, and 800 carriers, accompanied by three European sloops. In 1801, one naval division was reported to have included nine European vessels armed with 60 guns, five vessels with 50 guns, 40 with 16 guns, 100 junks, 119 galleys, and 365 smaller boats.

Most of the European-style vessels were built in the shipyard that Nguyễn Ánh had commissioned in Saigon. He took a deep personal interest in the naval program, directly supervising the work and spending several hours a day at the dockside. One witness noted "One principal tendency of his ambition is to naval science, as a proof of this he has been heard to say he would build ships of the line on the European plan." By 1792, fifteen frigates were under construction, with a design that mixed Chinese and European specifications, equipped with 14 guns. The Vietnamese learned European naval architecture by dismantling an old European vessel into its components, so that Vietnamese shipbuilders could understand the separate facets of European shipbuilding, before reassembling it. They then applied their newfound knowledge to create replicas of the boats. Nguyễn Ánh studied naval carpentry techniques and was said to be adept at it, and learned navigational theory from the French books that Pigneau translated, particularly Denis Diderot and Jean le Rond d'Alembert's Encyclopédie. The Saigon shipyard was widely praised by European travelers.

Despite his extensive reliance on French officers in matters of military technology, Nguyễn Ánh limited his inner military circle to loyal Vietnamese. The Frenchmen decried his refusal to take their tactical advice. Chaigneau reported that the Europeans continually urged Nguyễn Ánh to take the initiative and launch bold attacks against Tây Sơn installations. Nguyễn Ánh refused, preferring to proceed slowly, consolidating his gains in one area and strengthening his economic and military base, before attacking another. In the first four years after establishing himself in Saigon in 1788, Nguyễn Ánh focused on tightening his grip on the Gia Dinh area and its productive rice paddies, and although his forces exerted a degree on control over areas to the north such as Khanh Hoa, Phu Yen and Binh Thuan, their main presence in the northern areas were mainly through naval forces and not concentrated on land occupation. This was because those areas were not very fertile in terms of rice production and were often affected by famines, and occupying the land would have meant an obligation to feed the populace, putting a strain on resources. During this four-year period, Nguyễn Ánh sent missions to Siam, Cambodia and south to the Straits of Malacca and purchased more European military equipment.

Over time, Nguyễn Ánh gradually reduced the military role of his French allies on the battlefield. In the naval battle at Thi Nai in 1792, Dayot led the Nguyễn naval attack, but by 1801, a seaborne offensive in the same area was led by Nguyen Van Truong, Vo Duy Nguy and Lê Văn Duyệt, with Chaigneau, Vannier, and de Forsans in supporting positions. The infantry attack on Qui Nhơn in 1793 was conducted, according to Nguyen historiography, in cooperation with "Western soldiers". The same source recorded that by 1801, Nguyen operations in the same area were directed by Vietnamese generals, whereas Chaigneau and Vannier were responsible for organizing supply lines.

Unification of Vietnam

Vietnamese "Tirailleur" soldiers of the Nguyễn dynasty

In 1792, the middle and the most notable of the three Tây Sơn brothers, Nguyễn Huệ Quang Trung, who had gained recognition as Emperor of Vietnam by driving the Lê dynasty and China out of northern Vietnam, died suddenly. Nguyễn Ánh took advantage of the situation and attacked northwards. By now, the majority of the original French soldiers, whose number peaked at less than 80 by some estimates, had departed. The majority of the fighting occurred in and around the coastal towns of Nha Trang in central Vietnam and Qui Nhơn further to the north in Bình Định Province, the birthplace and stronghold of the Tây Sơn.

Nguyễn Ánh began by deploying his expanded and modernized naval fleet in raids against coastal Tây Sơn territory. His fleet left Saigon and sailed northward on an annual basis during June and July, carried by southwesterly winds. The naval offensives were reinforced by infantry campaigns. His fleet would then return south when the monsoon ended, on the back of northeasterly winds. The large European wind-powered vessels gave the Nguyễn navy a commanding artillery advantage, as they had a superior range to the Tây Sơn cannons on the coast. Combined with traditional galleys and a crew that was highly regarded for its discipline, skill and bravery, the European-style vessels in the Nguyễn fleet inflicted hundreds of losses against the Tây Sơn in 1792 and 1793.

In 1794, after a successful campaign in the Nha Trang region, Nguyễn Ánh ordered de Puymanel to build a citadel at Duyen Khanh, near the city, instead of retreating south with the seasonal northeasterly breeze. A Nguyen garrison was established there under the command of Nguyễn Ánh's eldest son and heir, Nguyễn Phúc Cảnh, assisted by Pigneau and de Puymanel. The Tây Sơn laid siege to Duyen Khanh in May 1794, but Nguyen forces were able to keep them out. Shortly after the siege ended, reinforcements arrived from Saigon and offensive operations against the Tây Sơn duly resumed. The campaign was the first time that the Nguyễn were able to operate in Tây Sơn heartland during an unfavorable season. The defensive success of the citadel was a powerful psychological victory for the Nguyễn, demonstrating their ability to penetrate Tây Sơn territory at any time of the year. The Nguyễn then proceeded to slowly erode the Tây Sơn heartland.

Heavy fighting occurred at the fortress of Qui Nhơn until it was captured in 1799 by Nguyen Canh's forces. However, the city was quickly lost and was not regained until 1801. The superior firepower of the improved navy played the decisive role in the ultimate recapture of the city, supporting a large overland attack. With the capture of their stronghold at Qui Nhơn, the vanquishing of the Tây Sơn was inevitable. In June, the central city of Huế, the former capital of the Nguyễn, fell and Nguyễn Ánh crowned himself emperor, under the reign name Gia Long. A common modern myth about this reign title is that was derived from Gia Định (Saigon) and

Thăng Long (Hanoi) to symbolise the unification of northern and southern Vietnam, despite no contemporary evidence supporting this. He then quickly overran the north, with Hanoi captured on 22 July 1802. After a quarter-century of continuous fighting, Gia Long had unified these formerly fractious territories, ultimately leading what is now modern Vietnam and elevated his family to a position never previously occupied by any Vietnamese royalty. Vietnam had never before occupied a larger landmass. Gia Long became the first Vietnamese ruler to reign over territory stretching from China in the north, all the way to the Gulf of Siam and the Cà Mau peninsula in the south. Gia Long's then petitioned the Qing dynasty of China for official recognition, which was promptly granted. The French failure to honor the treaty signed by Pigneau meant Vietnam was not bound to cede the territory and trading rights that they had promised.

Due to a Tây Sơn massacre of ethnic Chinese, the Nguyễn were subsequently supported by most ethnic Chinese against the Tây Sơn. The Tây Sơn's downfall and defeat at the hands of Nguyễn Phúc Ánh was therefore due, at least in part, to the ethnic Chinese support given the Nguyễn.

Rule

Gia Long's rule was noted for its strict Confucian orthodoxy. Upon toppling the Tây Sơn, he repealed their reforms and reimposed classical Confucian education and civil service systems. He moved the capital from Hanoi in the north to Huế in central Vietnam to reflect the southward migration of the population over the preceding centuries. The Emperor built new fortresses and a palace in his new capital. Using French expertise, Gia Long modernized Vietnam's defensive capabilities and, in recognition of the assistance of his French friends, he permitted the activities of Catholic missionaries, something, however, which was less tolerated by his successors. Under Gia Long's rule, Vietnam strengthened its military dominance in Indochina, expelling Siam from Cambodia and turning it into a vassal state. Despite this, he was relatively isolationist in outlook towards European powers.

Renaming Vietnam

Gia Long decided to join the Imperial Chinese Tributary System. He sent an embassy to Qing China and requested to change his country's name to Nam Việt (南越). Gia Long explained that the word Nam Việt derived from An Nam (安南) and Việt Thường (越裳), two toponyms mentioned in ancient Chinese records that were located in northern and southern Vietnam respectively, to symbolize the unification of the country. The Qing Jiaqing Emperor of China refused his request because it had an identical name with the ancient kingdom of Nam Việt (Nanyue), and the territory of Nam Việt contained Liangguang which belonged to Qing China at that time. Instead, Jiaqing agreed to change it to Việt Nam (越南). Gia Long's Đại Nam thực lục contains the diplomatic correspondence over the naming.

However, Gia Long copied the Imperial Chinese system, basing it on the Chinese Confucian model and attempting to create a Vietnamese Imperial tributary system. In 1805, Gia Long used "Trung Quốc" (中国), the very same word and characters used to refer to China, as a name for Vietnam.

It was said "Hán di hữu hạn" (汉夷有限, "the Vietnamese and the barbarians must have clear borders") by the Gia Long Emperor (Nguyễn Phúc Ánh) when differentiating between Khmer and Vietnamese. Minh Mạng implemented an acculturation integration policy directed at minority non-Vietnamese peoples. Thanh nhân (清人 Qingren) was used to refer to ethnic Chinese by the Vietnamese while Vietnamese called themselves as Hán nhân (汉人 Hanren) in Vietnam during the 1800s under Nguyễn rule.

Administrative structure

During the war era, Nguyễn Ánh had maintained an embryonic bureaucracy in an attempt to prove his leadership ability to the people. Due to the incessant warfare, military officers were generally the most prominent members of his inner circle. This dependency on military backing continued to manifest itself throughout his reign. Vietnam was divided into three administrative regions. The old patrimony of the Nguyễn formed the central part of the empire (vùng Kinh Kỳ), with nine provinces, five of which were directly ruled by Gia Long and his mandarins from Huế. The central administration at Huế was divided into six ministries: Public affairs, finance, rites, war, justice, and public works. Each was under a minister, assisted by two deputies and two or three councilors. Each of these ministries had around 70 employees assigned to various units. The heads of these ministries formed the Supreme Council. A treasurer-general and a Chief of the Judicial Service assisted a governor-general, who was in charge of a number of provinces. The provinces were classified into trấn and dinh. These were in turn divided into phủ, huyện and châu. All important matters were examined by the Supreme Council in the presence of Gia Long. The officials tabled their reports for discussion and decision-making. The bureaucrats involved in the Supreme Council were selected from the high-ranking mandarins of the six ministries and the academies.

Gia Long handled the northern and southern regions of Vietnam cautiously, not wanting them to be jarred by rapid centralization after centuries of national division. Tonkin, with the administrative seat of its imperial military protector (quan tổng trấn) at Hanoi, had thirteen provinces (tổng trấn Bắc Thành), and in the Red River Delta, the old officials of the Le administration continued in office. In the south, Saigon was the capital of the four provinces of Cochinchina (tổng trấn Gia Định), as well as the seat of the military protector. The citadels in the respective cities directly administered their military defense zones. This system allowed Gia Long to reward his leading supporters with highly powerful positions, giving them almost total autonomy in ordinary administrative and legal matters. This system persisted until 1831–32, when his son Minh Mạng centralized the national government.

In his attempts to re-establish a stable administration after centuries of civil war, Gia Long was not regarded as being innovative, preferring the traditional administration framework. When Gia Long unified the country, it was described by Charles Maybon as being chaotic: "The wheels of administration were warped or no longer existed; the cadres of officials were empty, the hierarchy destroyed; taxes were not being collected, lists of communal property had disappeared, proprietary titles were lost, fields abandoned; roads bridges and public granaries had not been maintained; work in the mines had ceased. The administration of justice had been interrupted, every province was a prey to pirates, and violation of law went unpunished, while even the law itself had become uncertain."

Foreign military relations

During the 17th and 18th centuries, the Cambodian empire had been in decline and Vietnamese people migrated south into the Mekong Delta, which had previously been Khmer territory. Furthermore, Cambodia had been periodically invaded by both Vietnam and Siam. Cambodia lurched uneasily between both poles of domination as dictated by the internal strife of her two larger neighbors. In 1796, Ang Eng, a pro-Siamese king, had died, leaving Ang Chan, who was born in 1791. When Gia Long unified Vietnam, Eng was given investiture by Siam in order to hold out Vietnamese influence, but in 1803, a Cambodian mission paid tribute to Vietnam in attempt to placate Gia Long, something that became an annual routine. In 1807, Ang Chan requested formal investiture as a vassal of Gia Long. Gia Long responded by sending an ambassador bearing the book of investiture, together with a seal of gilded silver. In 1812, Ang Chan refused a request from his brother Ang Snguon to share power, leading to a rebellion. Siam sent troops to support the rebel prince, hoping to enthrone him and wrest influence from Gia Long over Cambodia. In 1813, Gia Long responded by sending a large military contingent that forced the Siamese and Ang Snguon out of Cambodia. As a result, a Vietnamese garrison was permanently installed in the citadel at Phnom Penh, the Cambodian capital. Thereafter, Siam made no attempts to regain control of Cambodia during Gia Long's rule.

Napoleon's aims to conquer Vietnam as a base to threaten Company rule in India never materialized, having been preoccupied by vast military ambitions on mainland Europe. However, France remained the only European power with permanent spokesmen in Vietnam during his reign.

Trade relations

Pigneau's aborted deal with France allowed Gia Long to keep his country closed to western trade. Gia Long was generally dismissive of European commercial overtures. This was part of a policy of trying to maintain friendly relations with every European power by granting favors to none. In 1804, a British delegation attempted to negotiate trading privileges with Vietnam. It was the only offer of its kind until 1822, such was the extent of European disinterest in Asia during the Napoleonic Wars. Gia Long had purchased arms from British firms in Madras and Calcutta on credit, prompting the British East India Company to send John Roberts to Huế. However, Roberts's gifts were turned away and the negotiations for a commercial deal never started. The British then made a request for the exclusive right to trade with Vietnam and the cession of the island of Cham near Faifo, which was rejected, as were further approaches from the Netherlands. Both of these failed attempts were attributed to the influence of the French mandarins. In 1817, the French Prime Minister Armand-Emmanuel du Plessis dispatched the Cybele, a frigate with 52 guns to Tourane (now Da Nang) to "show French sympathy and to assure Gia Long of the benevolence of the King of France". The captain of the vessel was turned away, ostensibly on grounds of protocol for not carrying a royal letter from the French king.

Gia Long kept four French officers in his service after his coronation: Philippe Vannier, Jean-Baptiste Chaigneau, de Forsans and the doctor Despiau. All became high ranking mandarins and were treated well. They were given 50 bodyguards each, ornate residences and were exempt for having to prostrate before the emperor. Recommendations from French officials in Pondicherry to Napoleon Bonaparte suggesting the re-establishment of diplomatic relations with Vietnam were fruitless due to the preoccupation with war in Europe. However, French merchants from Bordeaux were later able to begin trading with Vietnam after the further efforts of the Duc de Richelieu.

Domestic policies and capital works

Gia Long abolished all large landholding by princes, nobles, and high officials. He dismantled the 800-year-old practice of paying officials and rewarding or endowing nobles with a portion of the taxes from a village or a group thereof. Existing highways were repaired, and new ones constructed, with the north–south road from Saigon to Lạng Sơn put under restoration. He organized a postal service to operate along the highways and public storehouses were built to alleviate starvation in drought-affected years. Gia Long enacted monetary reform and implemented a more socialized agrarian policy. However, the population growth far outstripped that of land clearing and cultivation. There was little emphasis on innovation in agricultural technology, so the improvements in productivity were mainly derived from increasing the amount of cultivated farmland.

Although the civil war was over, Gia Long decided to add to the two citadels that had been built under the supervision of French officers. Gia Long was convinced of their effectiveness and during his 18-year reign, a further 11 citadels were built throughout the country. The majority were built in the Vauban style, with pentagonal or hexagonal geometry, while a minority, including the one in Huế, were built in a four-sided traditional Chinese design. The fortresses were built at Vinh, Thanh Hóa, Bắc Ninh, Hà Tĩnh, Thái Nguyên and Hải Dương in the north, Huế, Quảng Ngãi, Khánh Hòa and Bình Định in the centre, and Vĩnh Long in the Mekong Delta. Construction was at its most intense in the early phase of Gia Long's reign, only one of the 11 was built in the last six years of his rule. De Puymanel and Lebrun left Vietnam before the end of the war, so the forts were designed by Vietnamese engineers who oversaw the construction. The position of Citadel Supervision Officer was created under the Ministry of War and made responsible for the work, underlining the importance that Gia Long placed on fortifications. Gia Long's fortifications program was marred by accusations that the people labored all day and part of the night in all weather conditions, and that as a direct consequence, land went fallow. Complaints of mandarin corruption and oppressive taxation were often leveled at his government. Following his coronation, Gia Long drastically reduced his naval fleet, and by the 1810s, only two of the European-style vessels were still in service. The downsizing of the navy was mainly attributed to budgetary constraints caused by heavy spending on fortifications and transport infrastructures such as roads, dykes, and canals. However, in 1819, a new phase of shipbuilding was launched, with Gia Long personally supervising the dockyards.

Social policy

In order to train and recruit government officials, Gia Long revived the Confucian court examinations that had been abolished by the Tây Sơn. In 1803, he founded the National Academy (Quốc Tử Giám) at Huế. Its objective was to educate the sons of mandarins and meritorious students in Confucian classical literature. In 1804, Gia Long promulgated edicts establishing similar schools in the provinces, as well as guidelines to regulate their staff and curriculum. He appointed Directors of Education (quan đốc học) to oversee the provincial education system and the selection process for the entrance examinations to the National Academy, beginning in 1802. The Directors were assisted by Subordinate and Assistant Directors (phó đốc học or trợ-giáo). Gia Long explained to his court in 1814 that the goal was to create a cadre of classically educated, politically loyal administrators:

In 1807, Gia Long opened the first civil service examinations held under the Nguyễn dynasty, staged at regional level. From then on, the training and selection process for the imperial bureaucracy was largely centered on examinations. The curriculum for the examinations consisted of the Four Books and Five Classics, which focused on Chinese history leading up to the Song dynasty, while regarding other knowledge as irrelevant.

Gia Long promulgated a new legal code to replace the system that had existed since the Hong Duc era of Lê Thánh Tông in the 15th century. Work started in 1811 under a group of scholars led by Nguyễn Văn Thành, and in 1815, the Bộ luật Gia Long (Gia Long Code) was issued. Although Gia Long claimed that his new system was a mixture of the Le code and Qing dynasty system of China, most scholars regard it as being a near-complete copy of the Qing code. The code was later translated into French by Paul-Louis-Félix Philastre. It focused on strengthening the power and authority of the emperor, his mandarins, and the traditional family unit. In cases of serious crimes, particularly those against the state, collective punishment was meted out to the family of the convict, including the death penalty.

Now that Vietnam was unified, the center of gravity of the country moved further south, following centuries of southerly migration and conquest, so Gia Long moved the seat of government from Hanoi to Huế. Gia Long rebuilt the old citadel of Phú Xuân into a fortress stronghold. The structure was a square shape of 2.5 km per side. A 9 m rampart was encased with masonry and protected by protruding bastions, each defended by 36 guns. The exterior and interior were flanked and reinforced by a series of moats. The citadel's defenders included an 800-strong elephant troop. The new palace structure, protocol and court dress were all taken directly from Qing dynasty styles, and his palace and fortress was intended to be a smaller copy of the Chinese Forbidden City in the 1800s.

Gia Long tolerated the Catholic faith of his French allies and permitted unimpeded missionary activities out of respect to his benefactors. The missionary activity was dominated by the Spanish in Tonkin and French in the central and southern regions. At the time of his death, there were six European bishops in Vietnam. The population of Christians was estimated at 300,000 in Tonkin and 60,000 in Cochinchina. However, he expressed dismay at the Catholic condemnation of the traditional ancestor worship, a basic tenet of Vietnamese culture. Gia Long was also known for his disdain for Buddhism, the religion practiced by the majority of the population. Despite its popularity among ladies of the court, Gia Long often restricted the activities of Buddhists.

In August 1802, Gia Long retaliated against the captured Tây Sơn leadership who had executed his family in the 1770s. The surviving members of the family and its leading generals and their families were executed. The remains of Quang Trung and his queen were exhumed and desecrated, and his son, the last Tây Sơn monarch Quang Toản was bound to four elephants and torn apart. Gia Long repealed the changes enacted by Quang Trung and reverted to the prior Confucian orthodoxy. This included restoring the civil service to the forefront of decision making, ahead of the army, and reversed Quang Trung's education reforms, which put science before the study of Confucian literature.

Family and succession

Minh Mạng, Gia Long's fourth son and successor.

Gia Long had many wives, but the most famous consorts are Empress Thừa Thiên, Empress Thuận Thiên, and Consort Lê Ngọc Bình.

In 1780, during the war against the Tây Sơn, he married Tống Thị Lan, the daughter of a Nguyen general. They had two sons, the first being Nguyễn Phúc Chiêu, who died shortly after birth in Phú Quốc island, and later Crown Prince Nguyễn Phúc Cảnh. Following Gia Long's ascension to the throne, she became Empress consort and was given the title of Empress Thừa Thiên posthumously. Around 1781, during the war with the Tây Sơn, he married his second wife Trần Thị Đang, a daughter of one of his ministers. They had three sons, Nguyễn Phúc Đảm, Nguyen Phuc Dai and Nguyen Phuc Chan, and was posthumously given the title of Empress Thuận Thiên. After his conquest of Vietnam, Gia Long, took his third wife, Lê Ngọc Bình. A daughter of Lê Hiển Tông, the penultimate emperor of the Lê dynasty, she was betrothed by Emperor Quang Trung to his son Quang Toản. After Gia Long defeated the Tây Sơn and executed Quang Toan, he took her as his wife. Gia Long had almost 100 concubines who were daughters of his mandarins; Gia Long did not favor polygamy but he did so to secure the loyalty of his inner circle.

As Crown Prince Nguyen Canh had died of smallpox during the war against the Tây Sơn, it was assumed that Canh's son would succeed Gia Long as emperor, but in 1816 Nguyễn Phúc Đảm, the son of his second wife, was appointed instead, and ruled as Minh Mạng. Gia Long chose him for his strong character and his deep aversion to westerners, whereas Canh's lineage had converted to Catholicism and were reluctant to maintain their Confucian traditions such as ancestor worship. Before his accession, Nguyễn Phúc Đảm was reported to have praised the Japanese for having expelled and eradicated Christianity from their country. Gia Long told his son to treat the Europeans respectfully, especially the French, but not to grant them any position of preponderance. Gia Long died on 3 February 1820 and was buried at the Thien Tho Tomb and posthumously named Thế Tổ Cao Hoàng đế.