Of Arab origin, and rebuilt in the 12th century by the Portuguese monarch Alfonso Enríquez, it was later consolidated by the Templars, becoming one of the most important bastions of this Order.
Originally it was made up of a triple enclosure, the intermediate one reinforced with cubes pointing towards the south. It is presided over by a powerful keep, completing the complex with a good parade ground, cisterns, dungeons, chapel and other rooms of which various remains are preserved.
Today the Interpretation Center of the Fortifications of the Great Lake of Alqueva is located inside and is preparing to house a unique space for conventions, congresses and exhibitions with the possibility of lodging.