Serpa, a border town with frequent conflicts, was, on the eve of the "Reconquista", an important fortified town, dominating fertile farmland. The old wall, built on the top of a small hill, delimited an area of around 21,000 square metres. At the end of the 13th century, King Dinis, in an effort to reorganise the Alentejo region in Christianity, refounded the Muslim town and ordered the construction of the fortress and an imposing urban wall covering 65,000 square metres from scratch.
It is quite possible that the bell tower of the Church of Santa Maria itself, which encloses a cylindrical structure inside, is a living testament to the minaret of the old mosque.