Alfonso's daughter, the "infanta" Sancha of León, married Ferdinand, Count of Castile. Sancha's brother, Bermudo III, declared the war against Castile and Castilian troops, with the help of Navarre, killed the Leonese king, becoming Ferdinand I of León. He and his queen gave the crucifix that bears their name to San Isidoro. The church also benefited from its position on the famous pilgrimage route to Santiago de Compostella. Sculptors, stonemasons and artists from across Europe gathered to work on the monastery.