Built by Juan V in 1724, and composed of three huge rooms, with furniture in rare woods and sumptuous giltwood Baroque decoration. Chinoiserie mtifs are painted onto the surfaces, the colour different for each room: green, red or gold. The trompe-l'oeil work on the ceilings is by Lisbon artists working in the Italianate taste. Access to the upper levels is by steps inside the pillars. 30 000 books and 5 000 manuscripts are organised by subject matter.