The validity of historic or ancient title to territory has been tested in numerous international judicial proceedings, both in the International Court of Justice and in international arbitration. Historic title usually originates in ancient normative systems, including tributary, feudal, sultanate, and Islamic systems that predate the Western international legal system. Nevertheless, the rules against which historic title has been tested in international judicial proceedings generally require that the original titleholder be a state or a central authority that exercised territorial sovereignty over a defined space to the exclusion of other sovereign powers. The rules that apply specifically to these ancient normative systems, where allegiance to authority was personal or religious rather than territorial, have been seen as irrelevant compared to the more contemporary determinations of historic title. The only exceptions have been the French medieval customary norm frankalmoign, which the international arbitral tribunal in the Minquiers and Ecrehos case cited as evidence that the English king exercised territorial sovereignty over the disputed islands, and the personal allegiance of the Orang Laut to the Sultan of Johore, coupled with the recognition accorded to the latter by the great maritime powers, which the International Court of Justice in Malaysia v. Singapore found sufficient to prove the historic title of Malaysia over Pedra Branca/Pulau Batu Puteh and Middle Rocks. The principles by which historic title were adjudicated in these cases appear to be the same principles by which the Western powers dealt with the claims of the People's Republic of China and Vietnam to the Paracel Islands and the Spratly Islands, not only during the colonial period but also after the Second World War. This analysis suggests how the International Court of Justice or an international arbitral tribunal might, if given the opportunity, resolve these South China Sea disputes. Readers might also find this analysis to be particularly relevant to other disputes involving historic title, including the East China Sea disputes, although the focus of this article is on the South China Sea disputes. States and other commentators are left to rely on their own preferences and allegiances in reaching their own normative conclusions using the novel analysis provided by this article.