The Spanish considered their war with the Muslims in Southeast Asia an extension of the Reconquista, a centuries-long campaign to retake and rechristianize the Spanish homeland which was invaded by the Muslims of the Umayyad Caliphate. The Spanish expeditions into the Philippines were also part of a larger Ibero-Islamic world conflict that included a war against the Ottoman Caliphate which had just invaded former Christian lands in the Eastern Mediterranean and which had a center of operations in Southeast Asia at its nearby vassal, the Sultanate of Aceh.