Original: The last Muslim ruler of Granada, Muhammad XII, better known as King Boabdil, surrendered his kingdom to Isabella I of Castile, who with her husband Ferdinand II of Aragon were known as the Catholic Monarchs (los Reyes CatÃ licos).
Simplified: The last Muslim ruler of Granada surrendered (gave up) his kingdom to Ferdinand II of Aragon and Isabella I of Castile, the Catholic kings (los Reyes CatÃ licos).