Background
He was the grandson of James II of Aragon and cousin of Pedro IV "the Ceremonious".
Duke of Gandia Constable of Castile
He was the grandson of James II of Aragon and cousin of Pedro IV "the Ceremonious".
He held the titles of Duke of Gandia (from 1399), Count of Denia (since 1355), Count of Ribagorza (from 1361), Marquis of Villena (since 1366), and first Constable of Castile. He was a claimant to the Crown of Aragon in the succession crisis that followed the death of Martin of Aragon with no children. Alfonso claimed the crown as senior male-line descendant of James World War II