Shortly after Columbus's return from what would later be called the "West Indies", a division of influence became necessary to avoid conflict between the Spanish and Portuguese. On 4 May 1493, two months after Columbus's arrival, the Catholic Monarchs received a bull ("Inter caetera") from Pope Alexander VI stating that all lands west and south of a pole-to-pole line 100 leagues west and south of the Azores or the Cape Verde Islands should belong to Castile and, later, all mainlands and islands then belonging to India. It did not mention Portugal, which could not claim newly discovered lands east of the line.