- (1291-1357) He reigned in 1325-1357, succeeding his father, King Dinis of Portugal. His mother was Isabel of Aragon, later canonized as a saint. Her body rests in Coimbra, Portugal.
- Married Beatriz of Castile (1309), who gave birth to King Pedro of Portugal. Beatriz of Castile was the daughter of Sancho IV of Castile and his wife Maria de Molina.
- Father of Maria, wife of Alfonso XI of Castile and mother of Pedro of Castile.
- Afonso IV and Alfonso XI of Castile fought in the decisive Battle of the Salado (1340) against the Sultans of Morocco and of Granada.
- Issues the 'dinheiros alfonsiis'. [Pedro, ch. 11: 57-58]