[1] In 1194, King Sancho conceded this region of the Northern Tagus River, then known as Guidintesta, or Guidi in testa (or still of Costa), to Afonso Paes, prior of the Order of the Hospitallers.

Between 1336 and 1341, Belver fell under the most important command of the Hospitallers, while still not seat nor official House, which continued to reside in the town of Leça do Balio.

The castle gates are located on the south face, anticipated by a staircase of masonry stone, and flanked by two towers, whose design would be used by King Denis.

[1][2][6] The walls and battlements which encircle the Castle follow a semi-circular oval around the keep, and are covered in parapets and turrets, with strategically place cubicle towers located around the entranceway and in each direction of the compass.

[2] The Traitor's Gate, the secondary access to the castle, is located on the cliff side of the structure, guarded by a round tower.

[1][7] Remains of the alcaide's residence and garrison are located in the south-east, south and south-west parts of the castle, in the space occupied by the three archways.

[2] In the interior of chapel is a high-altar, with a number of busts and reliquaries from Palestine, presented by the Great Prior of Crato to Prince Luís, son of Manuel I of Portugal.