In 1479 Portugal and Castile signed the Treaty of Alcáçovas ending the War of the Castilian Succession. During the war Castile had contested the Portuguese slave trade monopoly by threatening Portuguese outposts and unsuccessfully attacking their fleet in the Gulf of Guinea. With their main European rival neutralized, Portugal grew their trade networks and settlements in West Africa essentially unopposed throughout the 15th century. During that century various Portuguese settlers, adventurers, and merchants traveled to the coastal areas and archipelagos of West Africa—particularly Cabo Verde—either voluntarily or by force. Some were merchants or agents of commercial enterprises who "threw themselves" willingly ("lançavam") into contact with African peoples for trading purposes, and often circumvented the Portuguese monarchy's monopolistic taxes. However, the majority of "lançados" were legally or self-exiled to Africa, including Jews and New Christians escaping the Portuguese Inquisition, and persons called "degredados" serving out legally-imposed exiles. A very small minority of "lançados" were not Portuguese, but Spanish, Greek, or Indian.