Castelo dos Mouros is a hilltop medieval castle located in the central Portuguese civil parish of Santa Maria e São Miguel, in the municipality of Sintra, about 25km northwest of Lisbon.
The castle was constructed during the 8th and 9th centuries, during the period of Muslim Iberia, as the central place in a territory that was primarily agricultural, and which was necessary to protect its population.
In 2001 there were various interventions associated with cleaning the property, clearing undergrowth and forest overgrowth, and the installation of an electrical box along one of the walls.
The castle was restored in the 19th century by King Ferdinand II, who transformed it into a romantic ruin and a major feature of the gardens of the Pena Palace.
On 26 June 1996, declared the area of the Castle as a zone of special interest, by the Ministry of Culture.
It is classified as a National Monument, part of the Sintra Cultural Landscape.
It was an important strategic point during the Reconquista and was taken by Christian forces after the fall of Lisbon in 1147.
Since 1995 has been listed as a UNESCO World Heritage site.
The 1755 Lisbon earthquake caused considerable damage to the chapel and affected the stability of the castle.
A chapel with a rectangular nave and narrow, lower presbytery lies outside the secondary wall, not too far from the entrance. These ruins were constructed of limestone and masonry, and the interior is accessible from the western or southern façades.