Vietnam Institute of History
During their rule in Dang Trong (the South of Vietnam), the Nguyen Lords made great contributions to the nation’s historical development. They reclaimed virgin land in ThuanQuang region (the present-day provinces of QuangBinh, Quang Tri and ThuaThien-Hue) and at the same time further expanded their territory southward, creating Sai Gon – Gia Dinh region and its vicinities. In addition, the Nguyen Lords started establishing trade ties with regional countries like Japan and China as well as with western nations, including the Netherlands and Portugal. Especially with their seaward vision, the Nguyen Lords made great efforts in managing, controlling and establishing sovereignty over Hoang Sa (Paracel) and Truong Sa (Spratly) archipelagoes. The Nguyen Lords have handed down to posterity a strategic task of defending and maintaining the nation’s territorial waters in the East Sea, embracing Hoang Sa and Truong Sa archipelagoes.
Hoang Sa and Truong Sa regions rich in natural resources
According to historical documentation, Hoang Sa and Truong Sa regions are endowed with rich natural resources. It is recorded that offshore to the northeast of Binh Son district, Quang Ngai province, there are many islands and more than 130 mountains separated by waters which can take from a few hours to a full day to travel from one island to another. Freshwater streams can be found on these mountains. A flat and large golden sand bank stretching over 30 miles distinguishes itself among these islands which are home to many swift nests and hundreds or thousands of birds of other kinds. There are many strange creatures on the sandbank. Among the volutes are the Indian volutes; on their ventral side are opaque beads, different from pearls, and as big as fingertips. There are also conches that can be used for furniture inlay, and Babylon shells. All mollusks here can be salted or cooked for food.
Moreover, Hoang Sa and Truong Sa archipelagoes occupy a specially important strategic position in the East Sea, which has, from time immemorial, become a blood-vessel sea lane from the Pacific to the Atlantic and further, with commercial ships from China, Japan, Korea, Macao and western countries travelling to Southeast Asia and the Indian Ocean. These islands have also been known as ideal storm shelters for seagoing vessels. All these were clearly evidenced by various cargoes, including sabers, coins, brassware, tin and lead ingots, guns, ivory, porcelain, beeswax, etc. collected in these areas from sunken ancient ships by the Vietnamese Hoang Sa and Bac Hai flotillas.
The Nguyen Lords’ exercise of management of Hoang Sa and Truong Sa sea areas
According to official historical documents and folk documents collected in coastal central localities, the Nguyen Lords established their management of Hoang Sa and Truong Sa archipelagoes very early. Troops dispatched to patrol in Hoang Sa and Truong Sa regions had to get the Nguyen Lords’ permission before joining the marine patrol and control forces.
For effective management of island and sea areas, particularly Hoang Sa and Truong Sa archipelagoes, the Nguyen Lords founded Bac Hai flotilla with sailors selected from TuChinh village in BinhThuan province and Canh Duong commune. Those who join the flotilla would be granted permits by the Nguyen Lords and exempted from poll tax or river-crossing charges. It is recorded in historical documents that Bac Hai flotilla operated in a fairly large sea area belonging to southern and southern central provinces of Vietnam, patrolling Con Dao (Poulo Condor) island and others islands in Ha Tien sea bordering on the present-day gulf of Thailand.
In addition to Bac Hai flotilla, the Nguyen Lords also founded Hoang Sa flotilla to conduct marine patrol and control, exploit marine products and collect ship-wrecked cargoes floating to Hoang Sa and Truong Sa areas. Hoang Sa flotilla was carefully prepared for every long voyage, first obtaining the permission of the Nguyen Lords, then preparing vessels and food. Historian Phan Huy Chu wrote in “Lich Trieu Hien ChuongLoai Chi” (Classified Rules of Dynasties):
“Hoang Sa flotilla was set up by the Nguyen Lords with 70 crewmembers chosen from An Vinh village (Ly Son of Quang Ngai) on a rotational basis. In the third month of every year, by order of the Nguyen Lords, the men sailed on five small vessels, bringing with them enough food for six months, and reached these islands after three full days. There, they were free to catch fishes for food and collect plenty of precious items. In the eighth month, the sailors returned to the mainland through ThuanAn estuary, then they came to Phu Xuan citadel to hand over items they have collected.”
Having availed themselves of the advantage that inhabitants in Quang Ngai in particular and southern coastal provinces in Central Vietnam in general were experienced seafarers, the Nguyen Lords established Hoang Sa and Bac Hai flotillas to patrol a vast marine region and islands, including Hoang Sa and Truong Sa. The above-cited historical document written by scholar Phan Huy Chu shows that Vietnam was well aware of the location and importance of Hoang Sa and Truong Sa archipelagoes during the period of the Nguyen Lords. As recorded, it took three full days for the Vietnamese vessels to reach Hoang Sa and Truong Sa. The sailors would stay there for five or six months to perform their duties then return to Phu Xuan citadel, the seat of the Nguyen Lords, for reporting on the situation there and the performance of their duties.
By then, the feudal China was ruled by the Qing dynasty (from 1636 to 1912). All maps drawn by the Chinese feudalists then show that their southernmost point is the present-day Hainan Island bordering on Vietnam’s Hoang Sa archipelago frequently patrolled and controlled by Hoang Sa flotilla. According to historian Le Quy Don’s writing, Hoang Sa flotilla once on the way to Hoang Sa islands suffered strong winds and was drifted to a seaport of the Qing dynasty. The local Chinese mandarins notified the incident to the Nguyen Lords. Historian Le Quy Don wrote: “I saw an official letter sent by mandarins of Wenchang district, Qiongzhou province (China) to ThuanHoa (namely the Nguyen Lords), saying: In the 18th year of Quianlong (the reign name of the Qing emperor) (1753), in the seventh month 10 soldiers from An Vinh commune, ChuongNghia district, Quang Ngai province of An Nam (the Southern Part under the rule of the Nguyen Lords), arrived at Van Ly Truong Sa (Truong Sa archipalgo), eight going ashore to search for products while two others staying on their boat, which was then, due to strong winds, drifted away to Qinglan port. Local mandarins there sent them back to their native place. The Nguyen Lords ordered Thuc Luong, a mandarin, to write a letter of thanks.”
So, it can be clearly seen through this document how the Nguyen Lords organized the patrol and management of Hoang Sa and Truong Sa sea areas and islands, which was also acknowledged by the Chinese Qing dynasty through their notification of the incident to the Nguyen Lords.
Meanwhile, materials found in Ly Son district, Quang Ngai province, where young men joined Hoang Sa or Bac Hai flotilla, strongly confirmed the management of Hoang Sa and Truong Sa archipelagoes by the Nguyen Lords. At the ancestral worship house of the Vo family in An Vinh ward (present-day Tay hamlet, Ly Vinh commune, Ly Son district), a letter of request dated on the fifteen day of the first month of 1775 and signed by Ha Lieu, a mandarin of Re island ward, An Vinh commune, is still kept. The letter reads: “Our commune originally had Hoang Sa and Que Huong flotillas. In Tan Mui year (1631), Commander Vo He requested to set up two more flotillas: Dai Mao Hai Ba and Que Huong Ham with 30 members…”
Also in Re island ward, other materials provide more details about Hoang Sa flotilla and its sailors and their duties, which say: “Our commune originally had Hoang Sa and Que Huong flotillas… Now we restore them employing immigrants in the ward… We will sail to offshore islands to collect bronze and tin objects and tortoise shells to hand over to the royal court. In case of news about attacks of (foreign) invaders, we are willingly reassured to fight the invaders. After that, we will again ask for a royal permit to search for the treasures there and return them to the royal court.”
Through the above-cited materials, it can be realized that Hoang Sa and Bac Hai flotillas assumed sacred and courageous missions, not only patrolling the country’s sea areas and collecting products but also acting as warriors to defend the national territorial waters against foreign invasion.
In the Nguyen Lords’ time, specifically the 17th and 18th centuries, the seaward thinking as well as the tradition of defending the nation’s sea areas were further carried on and promoted. If during the previous dynasties of Ly, Tran and Le, the management of sea areas and islands by the royal court remained incomprehensive and at a low level, under the Nguyen Lords’ rule, the management and control of the nation’s sea areas and islands, especially Hoang Sa and Truong Sa, were carried out on a large scale with the establishment of separate and specialized forces.
It must be stressed that, Vietnam has, at least since the Nguyen Lords’ time, been the first nation to establish, reclaim, patrol and manage the sea areas of Hoang Sa and Truong Sa, which were then desolate and waste lands. It was Hoang Sa and Bac Hai flotillas set up by the Nguyen Lords that performed the duties of patrolling and managing these sea areas and islands on their behalf.
The historical evidences recorded in various documents and books during the Nguyen Lords’ period as well as materials kept in localities where inhabitants joined Hoang Sa and Bac Hai flotillas all affirm that Vietnam is the first to establish the national sovereignty over Hoang Sa and Truong Sa archipelagoes.
 Due to serious feuds between Trinh and Nguyen families, Nguyen Hoang in 1558 decided to settle in ThuanQuang region (namely Central Vietnam region, covering the provinces of QuangBinh, Quang Tri and ThuaThien-Hue). From then on, Dang Trong (the South of Vietnam) fell into the hands of the Nguyen Lords as counterpoise to Dang Ngoai (the North of Vietnam) managed by Le Kings and Trinh Lords. Dang Trong was ruled by nine lords: Nguyen Hoang (1558-1612), Nguyen Phuc Nguyen (1613-1634), Nguyen Phuc Lan (1635-1648), Nguyen Phuc Tan (1648-1687), Nguyen Phuc Tran (1687-1691), Nguyen Phuc Chu (1691-1725), Nguyen Phuc Chu (1725- 1738), Nguyen PhucKhoat (1738-1765), and Nguyen PhucThuan (1765-1775). Yet, the hostility between Dang Trong and Dang Ngoai actually began in 1672 and ended in 1788 when QuangTrung – Nguyen Hue smashed the Nguyen Lords’ forces in Dang Trong.
 After Nguyen Hoang moved to settle down in ThuanQuang region in 1558, Vietnam was divided into two zones: Dang Ngoai from the northern bank of Gianh river northward, which was ruled by Le Kings with Thang Long as the center (beside there existed then the Trinh family’s forces in this region), and Dang Trong stretching from the southern bank of Gianh river southward with ThuanHoa region (QuangBinh and Quang Tri) and Phu Xuan (Hue) as the center.
 Phan Huy Chu: Lich Trieu Hien ChuongLoai Chi, vol.1, Education Publishing House, Hanoi, 2007, pp.196-197.
 Le Quy Don: Complete works (Phu Bien tap luc (Miscellany on the Pacification at the Frontier)), Volumn 1, translated version, Social Science Publishing House, Hanoi, 1977, p.120.
 Nguyen Quang Ngoc: Hoang Sa, Truong Sa – Nhungtrangsuduocviet bang mau (Hoang Sa and Truong Sa – History written in blood), printed in Chu quyencua Viet Nam trenhaiquandao Hoang Sa va Truong Sa: Sucmanh den tutu lieu luutru (Vietnam’s sovereignty over Hoang Sa and Truong Sa: Power from archives), Information and Communications Publishing House, Ha Noi, 2015, p. 329.
 Letter of request of Re island ward, An Vinh commune, dated on the fifteen day of the first month of 1776 (kept at Vo family’s ancestral worship house in Tay hamlet, Ly Vinh commune, Ly Son district, Quang Ngai province, cited by Nguyen Quang Ngoc: Hoang Sa, Truong Sa – Nhungtrangsuduocviet bang mau (Hoang Sa and Truong Sa – History written in blood).