This is the last Portuguese coastal castle built according to the medieval style. It has an irregular layout that occupies the entire hill top. On the eastern side lies the fortress, made up of the donjon and turrets, while the rest of the perimeter is defined by the village’s wall, featuring turreted gates and ending in a tower on the western side.
In the 10th century, the castle was reinforced by the Omiad Emirate and finally conquered once again before 1199 by Frankish settlers. It enclosed Sesimbra until the 16th century. The renovation works executed between 1936 and 1941 halted a process of decay that had lasted for the past four centuries.
It was classified as a Monument of National Interest by a decree dated 16th June 1910, as well as Protected Area by a decree issued by the Ministry of Public Works and Communication (dated 9th October 1945) and by another decree issued by the Ministry of National Education, on 23rd September 1960.