Ferdinand I (of Castile and León), called The Great (1005?-65), king of Castile (1035-65) and of León (1037-65); he was the second son of King Sancho III of Navarre. Ferdinand married Sancha, the sister of Bermudo III, king of León, and heiress to the throne of León. In 1037 Ferdinand defeated Bermudo in a battle at Tamaron, acquiring León through Sancha's right of succession. Ferdinand won the Battle of Atapuerca over his brother in 1054 and was recognized as the emperor of Spain in 1056. By his territorial acquisitions from the Moors between 1058 and 1065, Ferdinand inaugurated the period of Christian reconquest of Spanish land from the Muslims. Before his death Ferdinand provided that his estates be divided among his three sons, thus bequeathing a legacy of fratricidal strife that did not end until the accession of Alfonso I to the throne of Castile in 1072.