Ferdinand I, the Great, king of Castile, Leon, and Galicia, born about 1000, died in Leon, Dec. 27, 1065. He was the second son of Sancho el Mayor, king of Navarre. In 1033 he received the hand of Sancha, sister of Ber-mudo III. of Leon, and the title of king of Castile, which was henceforth recognized as an independent sovereignty. On the death of Sancho in 1035, Bermudo attempted to reannex the new state to his dominions; but he was defeated and slain by Ferdinand in 1037. The young king of Castile forthwith claimed and received the crown of Leon, in right of his queen; and by able management and forbearance he reconciled to his cause many lords who at first had opposed his accession to the throne. He soon gained popularity by his respect for the laws of the country, his maintenance of the ancient fueros, and his strict administration of justice. He invaded Portugal and acquired in 1045 a considerable portion of it. From 1046 to 1049 he was engaged in wars against the Moors, and reduced the kings of Saragossa and Toledo to tributaries.

His elder brother, Garcia III., king of Navarre, having attacked him in 1054, lost his life in a battle fought near Burgos, in the plains of Atapuerca. By this victory Ferdinand gained several districts which formerly belonged to Navarre, and became the most powerful among the Christian princes in the peninsula. In 1056 he took the title of emperor, to indicate his supremacy in Spain. Toward the centre of the peninsula, he extended the boundary of Castile to the gates of Alcala de Henares, and carried hostilities into Valencia and Andalusia, compelling the emir of Seville to swear allegiance and to restore to him the relics of St.

Isidro (1063). His last days were spent in extraordinary devotional exercises. Attacked by a sickness which he knew would be fatal, he returned to Leon, and divided his realms between his three sons.