[1][2][3] The first archival references to the construction project of a fort at Ameixoeira date from November 20, 1875.
Excavation and earth-removal work was completed only by the end of 1888 and the building was not finished until December 1901.
[1] In the context of the crisis that led to the fall of the First Portuguese Republic, the fort suffered an assault on 11 August 1924 as part of an attempted but unsuccessful military coup by supporters of Manuel Gomes da Costa.
After World War I, the concept of a fixed defence, on which the Campo Entrincheirado was based, became obsolete and the forts began to be used for other purposes.
On 28 September 1943 one of the storerooms exploded, killing six soldiers and completely destroying the south wing of the building.