The Fort of Sacavém was built into a small hill about 35 meters high, which gave it a strategic position over the surrounding area.

[2] In 1872 studies began for the construction of the redoubt at Sacavém and in 1875 part of the property of the Viscount of Ouguela was purchased as the site for the fort.

The ultimate plan was for nine permanent forts to be linked together between Sacavém and Caxias on the Tagus estuary and in 1902 a road was completed connecting the nine sites.

In 1998 the fort still had a small military force but in that year transfer to the Architectural Heritage Inventory Services (SIPA) was authorised.

The library is unique in the country, and is devoted to the dissemination of information on built heritage, especially in the areas of conservation, restoration and urban rehabilitation.

Once certified free of disease they are ready to be archived and inventoried and then stored in one of five different environments with different levels of humidity, air temperature and oxygen, according to the requirements of the individual documents.