Diplomatic Claims and Imperial Realities: Spain and Northern Borneo in the Nineteenth Century

The article examines the policy of the Spanish Empire toward northern Borneo during the nineteenth century and argues that there existed a structural contradiction between Spain’s diplomatic claims and its actual administrative practice. Although Spain occasionally invoked historical ties with the Sultanate of Sulu to justify claims of sovereignty, it never effectively incorporated Borneo into the administrative or legal framework of the Philippine colony. Drawing on the analysis of treaties, diplomatic correspondence, maps, and administrative records, the study demonstrates that the power of the Sultanate of Sulu and the pressure exerted by other powers—particularly the United Kingdom—prevented Spain from establishing effective control over Borneo.