For its architectural quality, and for its state of conservation, it is the most representative building of the Romanesque in Portugal. The façade has three protruding volumes, the largest of which is that of the axial portal. This axial portal has a decoration with an Islamic influence (texture, lace). This facade is topped by the battlements that reinforce the sense of fortress. On the facades we see some stones with the marks of the masons who worked them, and it is interesting that one of them up there is one containing an Arabic inscription, showing the peaceful integration of hand Muslim workforce in the 12th century.