[2] In 1211, King D. Sancho I constructed a royal palace and donated it to his daughter, Sancha, who would eventually take refuge there following a disagreement with her brother, the Infante D. Afonso II (who disagreed with their fathers gifting of the castle).

[1][2] In order to resolve the dispute between the siblings, Pope Innocent III placed the castle in charge of the Knights Templar in 1216, proving the military relevance of the structure at that time.

[2] The walls were covered by protected embattlements with rectangular merlons, and near the river, constructed as a defensive link to water resources was the "Torre da Couraça".

[1][2] After a period, the alcalde, Vasco Pires de Camões surrendered the fortifications, but as a reprisal for the former-alcalde's conspiracy against him, he ordered the removal of the cornerstones of the keep tower and lowered the walls.

[1] In the 19th century, the need to open a gateway between the Nossa Senhora da Conceição Gate and square, obliged the municipal authority to destroy part of the lower wall.

[1][2] Similar excavations in 1940 alongside the Nossa Senhora da Conceição Gate allowed archeologists to prove the existence of a prehistoric settlement on the site.

[1] As part of the archeological recovery of the site, the DGMEN demolished the chapel over the Gate, and proceeded to partially restore the walls, but the project was incomplete, and it remained unfinished.

[1] The left tower, with strong lower backstop, along with the one in the northeast, are surmounted by terrace and parapets, and the right by rectangular construction with tile roof and small belfry.

[1] The Gothic castle in Alenquer was organized into two enclosures: an upper courtyard, that conformed to the topography of the terrain, where the Muslim alcáova existed; and the inferior terrace that covered a much wider area, that protected the primitive urban agglomeration.