An Irish professor of international law - Anthony Carty - has spent considerable time looking through British and French archives, spanning from the 1880s until the late 1970s, to look at the historical understanding of sovereignty of the Spratly Islands. These are the islands in the South China Sea at the core of the present dispute between China and the Philippines.
He discovered that "the archives demonstrate, taken as a whole, that it is the view of the British and French legal experts that as a matter of the international law territory the Xisha Islands [the Paracel Islands] and the Nansha Islands [the Spratly Islands] are Chinese territory".
For instance on the Spratly islands he says: "French legal advice was that France never completed an effective occupation of the Spratlys, and they abandoned them completely in 1956. In the 1930s they recognized that these Spratlys had always been home to Chinese fisherman from Hainan Island and Guangdong. There had never been any Vietnamese or Philippine connection and French interference had only been in its own name and not that of Vietnam. It is the British who then drew a decisive conclusion, from all the French and British records available, that the Chinese were the owners of the Spratlys [the Nansha Islands], a legal position certified as part of British Cabinet records in 1974."
Fascinatingly, and immensely relevant to today's dispute between the Philippines and China, and America's involvement in the matter, he discovered "a record in the mid-1950s in the US National Archive, in which a US under secretary of state says that, while the Filipinos have no claim to the Spratlys, it is in the US interest to encourage them to make a claim anyway to keep Communist China out of the area".
His conclusion: "There is absolutely no doubt that this whole dispute is entirely about the Americans trying to make life difficult for the Chinese. The aggression that is building up against China and the scapegoating of China by the whole of the so-called democratic community of the world is appalling."
https://www.globaltimes.cn/page/202404/1310059.shtml