The grounds of the Escorial monastery include the Royal Palace, basilica, Pantheon of Kings, a library and a monastery. Built in the Renaissance Humanist style between 1563 and 1584, it once served as the seat of Spanish power and the the residence of the Royal family. Today, it is home to the monks of the order of St. Augustine. In the Pantheon of Kings, there are 26 marble graves of the Kings and Queens of the houses of Austria and Bourbon.