Original: Ferdinand was born in Sos del Rey Católico Aragon , and was the son of John II of Aragon ( whose family was a cadet branch of the House of Trastámara ) by his second wife , Juana Enríquez .
Simplified: At this point to reinforce his claim to the kingdom , Ferdinand remarried with the much younger Germaine of Foix ( 1490 -- 1538 ) , a granddaughter of Queen Leonor of Navarre .