 Ferdinand was barely in his teens when García Sánchez, Count of Castile, was assassinated by a party of exiled Castilian noblemen as he was entering the church of John the Baptist in León, where he had gone to marry Sancha, sister of Bermudo III, King of León.In his role as feudal overlord, Sancho III of Navarre nominated his younger son Ferdinand, born to the deceased count's sister Muniadona, as count of Castile.Although Sancho was recognised as the ruler of Castile until his death, Ferdinand was granted the title "count" ("comes") and was prepared to succeed in Castile.