Built on one of the medieval gateways to the city, this monumental archway was commissioned by Bishop Francisco Gomes de Avelar in the early 19th century. The project was carried out by Italian architect Francisco Xavier Fabri and inaugurated in 1812.
On an inner niche, there is an Italian made statue of Saint Thomas of Aquinas. It is one of the finest examples of the Italian neo-classical to be found across the Algarve.
Inside, it is still possible to make out the Arab entranceway. This was part of the old Muslim walls and represented the entranceway into the city for anyone arriving by sea. It is considered a unique example of Moorish architecture in Portugal taking into account both its high level of preservation and that it still remains in its place of origin.