At the top of the upper town is the stark, glowing-white, fortress-like former royal palace, now the Pousada de Rainha Santa Isabel. Dom Dinis built the palace in the 13th century for his new wife, Isabel of Aragon. Visitors are welcome to view the public areas of the pousada and climb the keep, which offers a superb panorama of the old town and surrounding plains.
After Isabel of Aragon鈥檚 death in 1336 (Dinis had died 11 years earlier), the palace was used as an ammunition dump. An inevitable explosion, in 1698, destroyed most of the palace and the surrounding castle, though in the 18th century Jo茫o V restored the palace for use as an armoury. The 27m-high keep, the Torre das Tr锚s Coroas (Tower of the Three Crowns), survived and is still the dominant feature. It鈥檚 so called because it was apparently built by three kings: Sancho II, Afonso III and Dinis.
The holes at the keep鈥檚 edges were channels for boiling oil 鈥 a good way of getting rid of uninvited guests.