The city's most important historical buildings include the Catedral Santa María La Menor, the first cathedral of the Americas, which states its distinction; the Alcázar de Colón, the first castle in the Americas, once the residence of Viceroy of the Indies Don Diego Colón, a son of Christopher Columbus; the Monasterio de San Francisco, the ruins of the first monastery in the Americas; the Museo de las Casas Reales, in a monumental complex that includes the former Palace of the Governors and the building of the former Royal Audiencia of Santo Domingo; the Fortaleza Ozama, the oldest fortress in the Americas; the Pantéon Nacional, a former Jesuit edifice now hosting the remains of various renowned Dominicans; and the Dominican Convent, the first convent in the Americas.