Ferdinand I of Portugal
The Third Fernandine War was the last conflict of the Fernandine Wars, and took place between 1381–1382, between the Crown of Castile and the Kingdoms of Portugal and England. When Henry II of Castile ("Henry of Trastamara") died in 1379, John of Gaunt, 1st Duke of Lancaster claimed their rights of the throne of the Kingdom of Castile, and found an ally Ferdinand I of Portugal.