Built in medieval times, the former Benedictine monastery of S. Salvador de Castro de Avelãs had a great influence on the settlement of the region, appearing in documentation from the 17th century. XIII as a religious institution holding great wealth and most powerful in Trás-os-Montes during the medieval period.

Extinct by the middle of the century. XVI (1545-1546), the same bull that created the Diocese of Miranda do Douro extinguished this monastery and, consequently, the building entered a process of degradation and dilapidation.
Of the original monastic complex, all that remains today, of genuine Cluniac Romanesque architecture, is the head of the temple, with a semicircular finish and brick cladding, with a clear inspiring influence from the Leonese art of Sahagun. The original plan would include three naves, with only the central one currently remaining.

Inside one of the apses, now open to the outside, there is a granite tomb chest.
Source: https://turismo.cm-braganca.pt/patrimonio-com-historia/igrejas-e-mosteiros/geo_artigo/mosteiro-de-castro-de-avelas