The Madrid Protocol of 1885 is an agreement between Great Britain, Germany and Spain to recognize the sovereignty of Spain over the Sulu Archipelago as well as the limit of Spanish influence in the region (Articles I and II). The most interesting point to note that under the agreement (specifically, Article III), Spain as the colonial power ruling the Philippines islands — including the Mindanao and Sulu areas — clearly relinquishes all claims to Borneo.

ARTICLE III
The Spanish Government renounces, as far as regards the British Government, all claims of sovereignty over the territories of the continent of Borneo, which belong, or which have belonged in the past to the Sultan of Sulu (Jolo), and which comprise the neighbouring islands of Balambangan, Banguey, and Malawali, as well as all those comprised within a zone of three maritime leagues from the coast, and which form part of the territories administered by the Company styled the “British North Borneo Company.”

Download the full document: Madrid_Protocol_1885 [.pdf format]