In Setúbal Peninsula, in the foothills east of the Arrábida mountains, is situated between the estuaries of the River Tagus and Sado river, near the mouth of the latter. Is part of the so-called Riviera, in the Arrábida Natural Park. On a clear day from the top of the castle one can see Lisbon.

During  the Christian Reconquest of the Iberian peninsula after the conquest of Lisbon (1147) by the forces of King Afonso Henriques (1112-1185), 3 cities have fallen in to the Portuguese domain : Sintra, Almada and Palmela.

At the time, the Muslim forces defending Palmela, abandoned it, and took  refuge in Alcácer do Sal. And the Portuguese forces only conquered the village and its domains. Muslim forces, however, soon reorganized, recovering south of the Tagus river. Christians reconquered Palmela in 1158.

Again lost, was finally conquered on June 24 1165. From the following year reinforcement works were undertaken.