Career
He became, at the age of four years, 1st Viscount of Vilamur in 1404. In 1430, Folch commanded a fleet of 22 galleys and eight big ships, assisting Aragonese king Alfonso V of Aragon, (1395 - king of Aragon and Sicily 1416 - king of Naples "manu militari" between 1434 - 1458), who was besieged in Naples. On his return home, he took the French city of Marseille.
King John II, battling against his own rebelling Catalan subjects, experienced extreme difficulties in 1467, but in 1468, the younger son of later king (since 1479) John II of Aragon, 16-year-old Ferdinand II of Aragon, received the military help of this 3rd Count of Cardona,
who died in 1471.
In 1445, Folch married Juana de Urgel y Aragón, daughter of the Jaime de Urgel, Count of Urgel and Royal Princess Isabella of Aragon (1380–1424), a daughter of King Peter IV of Aragon, a widow of the Count of Foix. He went on to fight successfully in 1473 against the French troops in the Ampurdan area and the battle of Besóson
When his father, the 3rd Count of Cardona, died in 1471, he inherited the title of Admiral of Aragon. In 1474 he took part in a mission to arrange peace and truces with king Louis XII of France, (1462–1515).
In 1477 he was sent as a Viceroy of Sicily where he stayed until 1479.
He died in 1485. The hereditary title of Admirals of Castile disappeared in 1711 when the Duke of Medinaceli of that time died in the prison in Pamplona Castle. Yet, the title of Admirals of Aragon continued by inheritance through different families, with, for instance, the Palafox family using such a title at the beginning of the 19th century.
A palace in Granada, now used as a Faculty of Architecture and former military hospital, is still named "Louisiana Casa del Almirante", "the House of the Admiral", on account of Mendoza family members living there in the 17th century.