- (1329-1363) Son of Alfonso IV of Aragon and his second wife Leonor, sister to Alfonso XI of Castile.
- Married to Maria of Portugal (1359), daughter of Pedro of Portugal. [Pedro, 41: 32-33]
- Brother of Prince Juan of Aragon. After his father passed away, antagonizing his step-brother, Pedro IV, by attempting to build his own faction, Fernando went into exile in Castile taking along his mother and his brother Prince Juan.
- The princes Fernando and Juan of Aragon, cousins of Pedro of Castile through their mother, Queen Leonor, sided with the faction of Blanche of Bourbon and refused to serve the king unless he returned to his lawful wife and ceased to bend to the influence of María de Padilla's brothers. [Pedro, ch. 17: 143-147]
- When Pedro of Castile killed Fernando's brother Juan, he joined Enrique de Trastámara's forces to invade Castile. [Pedro, ch. 22: 14-16]
- He even assisted Pedro IV of Aragon, his formerly estranged brother, in defending Aragon against Pedro of Castile's attacks. [Pedro, ch. 34: 50-54]
- Pedro IV of Aragon finally yielded to Pedro of Castle's demands to hand over Fernando of Aragon, but during his arrest he was killed, which brought much criticism against the king of Aragon (1363). [Pedro, ch. 34: 75-80]