[1] The fort was first used as a prison in 1916 when a group of soldiers who mutinied were arrested.
From 1935 the southern part of the fort was used by the Estado Novo dictatorship as a political prison, which included torture chambers, and this continued until Portugal’s Carnation Revolution, when its doors were opened on April 25, 1974.
The fort was transferred to Portugal’s Prison Service in December 1988.
[1][2] Although the fort was not generally used by the Estado Novo to accommodate the communist party’s top leaders, who were mainly held in the Peniche Fortress, it did witness a mass escape on 4 December 1961 when eight communist party members were able to escape in an armoured car, which they succeeded in smashing through the main gate.
The driver had taken a long time gaining the confidence of the guards by convincing them that he had rejected communism and was now on their side.