The Catalans and Aragonese offered themselves to the Byzantine Emperor Andronicus II Palaeologus to fight the Turks. Having conquered these, they turned their arms against the Byzantines, who treacherously slew their leaders; but for this treachery, the Spaniards, under Bernard of Rocafort and Berenguer of Entenca, exacted the terrible penalty celebrated in history as "The Catalan Vengeance" and seized the Frankish Duchy of Athens (1311). The royal line of Aragon became extinct with Martin the Humane, and the Compromise of Caspe gave the Crown to the House of Trastámara, already reigning in Castile.