They were handed over by Dang Thanh Tung, head of the State Records Management and Archives Department at a ceremony on Saturday.

He said the documents show the establishment and exercising of Vietnamese sovereignty over the Hoang Sa (Paracel) and Truong Sa (Spratly) islands by the Nguyen Dynasty, which ruled from 1802 to 1945.

They also include one, made public for the first time, which is a report by the Ministry of Revenue in 1869 detailing Da Nang authorities' allocation of rice to help 540 people from China's Fujian Province who got stranded on Truong Sa.

The imperial archives and the woodblocks of the Nguyen Dynasty are two especially important collections in Vietnam's archives with legal and historical value, Tung said.

The archives contain the administrative records of the Nguyen Dynasty and the signatures of the Nguyen kings, and are being preserved at the National Archives.

"We are very proud to be able to donate a part of the documents we are managing and archiving to the People's Committee of Hoang Sa Island District," Tung said.

He added that more key documents would be handed over to authorities in Da Nang and the central Khanh Hoa Province, which administers Truong Sa Islands, to "build databases with full historical and legal evidence to fight for the sacred territories of the fatherland."

Assoc Prof Dr Nguyen Tuan Cuong, director of the Institute of Han-Nom Studies, donated to Hoang Sa District authorities the 40-page "Hoang Le Canh Hung map" he had collected from Keio University in Tokyo, in which page 31b contains a description of the Yellow Sand Bank, or Hoang Sa Islands.

Other documents donated at the ceremony include a map of Hoang Sa Islands published by the French Navy in 1885 and reprinted in 1940 based on a survey conducted by the Germans in 1881-83, a research paper on the battles Vietnamese naval forces had fought to defend the country, paintings of Truong Sa Islands and propaganda posters promoting Vietnam's sovereignty over the islands, and a map of Tourane (French name for Da Nang at the time) published by the Indochina Geographical Department in November 1898 that clearly shows Hoang Sa Islands as part of the city.

According to Vo Ngoc Dong, chairman of Da Nang's Hoang Sa District, since 2016 the district has received 212 relics and documents of historical and legal importance from Vietnamese and foreign organizations and individuals confirming Vietnam's sovereignty over the Hoang Sa and Truong Sa islands.

Most sources of information and documents related to Hoang Sa Islands are now scattered around various archives, and Dong hoped the Hoang Sa Library, which would be situated inside the Hoang Sa Exhibition House, would gather all documents.

At the handover ceremony, Hoang Sa District authorities also met with and gave mementoes to people who used to work on the islands before 1974.

Tran Van Son, one of them, said: "We are very touched by the affection of the people across the country. There are still many people trying hard to search for documents to fight for our sovereignty, making me very happy."

Vietnam has long had and been exercising sovereignty over both the Hoang Sa and Truong Sa islands.

China seized Hoang Sa Islands from South Vietnam by force on January 19, 1974, and has since been illegally occupying them.