The Casa del Mono (House of the Monkey) is one of the best-preserved Gothic palaces in the Ciudad Monumental, built in the fifteenth century by a nobleman whose family crest — with its ambiguous animal — gave the building its popular name. The house is notable for its exterior Gothic window tracery and the carved stone portal, which shows the evolution from purely defensive architecture toward the more decorative Renaissance style that would arrive a generation later.
The building now houses the public library of the provincial museum system, which means it is open on weekdays and accessible to anyone who wants to walk in and look around the ground floor. The interior courtyard is Gothic in structure, with arched galleries on two levels, and the staircase is particularly fine.
The Casa del Mono stands close to the Church of San Mateo, and the two together form a good starting point for a walk through the quieter northern part of the old town, away from the main tourist concentration around the Plaza de Santa María.