Part of the Romanesque church was a Benedictine monastery from the 12th Century. Its progressive deterioration began with its abandonment and subsequent demolition for the purpose of reusing the materials in other constructions. In the 18th century a single nave church was built. The primitive north end apsidiole became the sacristy. In the 20th century, the south end apsidiole was reconstructed and in 2006 the cloister was discovered along with the conventual wings near the church.
What is interesting about this church is the construction material used. In addition to granite, bricks were used when creating the arcades and blind windows in the East end which have a clear Mozarabic influence. The main facade with pinnacles in the corners contains a front doorway with a straight lintel and a curved pediment. Further up, there is a rectangular opening finished off by a cross on the top.
Three archivolts adorned by grape leaves and vines make up the structure of the main Baroque altarpiece. The secondary altarpieces located on the wall of the triumphal arch show images like Saint John with the Child or the Sacred Heart of Jesus. There are also 12 paintings on the wall that represent the Passion of Christ. In the south apsidiole, there is a monolithic sarcophagus from the 13th century. In the interior there is an engraved inscription associated with the family who acted as patrons to this monastery. The two lions made of granite that supported the arch were transported to the main doorway.
The interventions in the church of Castro de Avelãs were established on the basis of a definition of its priorities. To do this, we first conducted a precise diagnosis of the building that could help achieve the ultimate goal of ensuring its future conservation through discrete interventions and always respecting the authenticity of the building.
In this first phase, we conducted an interdisciplinary work involving architects, archaeologists, engineers, restorers and conservators, in order to draft a proposal for appropriate intervention and proper scheduling of jobs. The initial diagnosis showed that the immediate needs should focus on the rehabilitation of the covers, to prevent all the problems related to filtrations. The substitution of coverage included the addition of a waterproof membrane. The restoration and improvement of the original wooden structure and the application of protective treatments accompanied this work. On the other hand, we also conducted the intervention in the hollows of the temple so we decided to discard the most recent woodwork and its replacement with other newly designed.