prince. By the end of August Prince John had succeeded his father as king. His main objective was to find a sea route to the East. Papal endorsement The bull confirmed the earlier bulls Romanus Pontifex, issued by Nicholas V in 1455. It also incorporated the terms already agreed to by Portugal and Castile in the Treaty of Alcáçovas, lending moral authority to the parties' territorial division. According to Malyn Newitt in A History of Portuguese Overseas Expansion, "Portuguese's ... empire was able to grow in a manner which would have been impossible if it had been challenged by a well-armed opponent." However, Isabella and Ferdinand were involved in the Granada War, England was embroiled in dynastic conflict, and Louis XI of France was drawn to the affairs of Italy. See also Catholic Church and the Age of Discovery Treaty of Tordesillas (1494) References Sources External links Latin text of Aeterni regis "The legal background of the Spanish claim and colonization of the Caribbean and the New World" 1481 works 1481 in Portugal 15th century in Castile 15th-century papal bulls Documents of Pope Sixtus IV