Alfonso IV, called the Kind (also the Gentle or the Nice, Catalan: Alfons el Benigne) (1299 – 24 January 1336) was the King of Aragon (as Alfonso III) from 1327 to his death. He was the second son of James II and Blanche of Anjou. His reign saw the incorporation of the County of Urgell, Duchy of Athens, and Duchy of Neopatria into the Crown of Aragon.
During the reign of his father, he was the procurator general of the Crown. He married Teresa d'Entença, heiress of Urgell, in 1314. In 1323–1324, he undertook the conquest of Sardinia. He became heir after his older brother James renounced his rights to become a monk. In 1329, he began a long war with the Republic of Genoa. The city of Sassari surrenderd in 1323, but rebelled three more times and was contested by Genoa.
After widowing, Alfonso married Eleanor of Castile, who was betrothed to his brother James, who had refused to consummate the marriage. She was the sister of Alfonso XI of Castile.

Children
By Teresa d'Entença:
By Eleanor of Castile:

Alfonso, lived only one year
Peter IV, successor
James I, Count of Urgell, also inherited Entença and Antillon
Fadrique, died young
Constance (1322-1346), married James III of Majorca
Elizabeth, died young
Sancho (1327), lived only a few days
Ferdinand, Marquis of Tortosa
John, married Isabel Núñez de Lara and was killed by order of his cousin Pedro of Castile