Original: Acquiring titles Ferdinand was  born in Sos del Rey Católico, and was the son of John II of Aragon (whose family was a cadet branch of the House of Trastámara) by his second wife, the Castilian noblewoman Juana Enríquez.
Simplified: Ferdinand was the son of John II of Aragon by his second wife, the Aragonese noblewoman Juana Enriquez.