For nearly 800 years, the Christian kingdoms of the Iberian Peninsula were fighting the Muslim invaders that held much of the land in modern day Spain and Portugal. This all changed in 1492, when armies of the Catholic Monarchs, Ferdinand of Aragon and Isabella of Castile, finally took the city of Granada, the last Muslim-ruled area of Spain. This was in some ways a foregone conclusion, as the unification of Ferdinand and Isabella's kingdoms meant that the Christian kingdoms were prosecuting a war for nearly a decade to slowly chip away the lands controlled by Muslim rulers. By 1491, Boabdil, the last Emir of Granada, knew that his time was up and negotiated a treaty to give up Granada. Nonetheless, the final reconquest of Spain by Christian armies changed the world, leading to the Spanish Inquisition, the voyage of Christopher Columbus, and a New World Empire for Spain.