John II of Portugal

He succeeded his father, Alfonso V, in August 1481. His first business was to curtail the overgrown power of his aristocracy; noteworthy incidents in the contest were the execution (1483) of the duke of Braganza for correspondence with Castile, and the murder, by the king's own hand, of the youthful duke of Viseu for conspiracy.

Maritime rivalry led to disputes between Portugal and Castile until their claims were adjusted by the famous Treaty of Tordesillas (June 7, 1494).

Supporting Portuguese exploration, he sent land expeditions to India and Ethiopia in search of Prester John and sent a vessel North past North Cape[?]. John refused to help Columbus, whom he thought a dreamer, but he encouraged the search for an eastern sea route to India. Diogo Cão discovered (1484) the Congo, and Bartolomeu Dias rounded (1488) the Cape of Good Hope during his reign.

John II died, without leaving male issue, in October 1495, and was succeeded by his first cousin Manuel I.