The Romanesque church at the east end of the Plaza Mayor was consecrated in 1181, though construction began earlier in the 11th century. The bell tower — square, solid, and taller than the nave — is the visual anchor of the old town and visible from the valley floor below.
Inside, the church is dark and plain in the way of Romanesque mountain architecture: thick stone walls, a single nave, minimal ornament. The crypt beneath the apse is the oldest part of the building and worth a look. Mass is still said here regularly.
The church was built to serve the medieval capital of Sobrarbe, and the solemnity of the interior reflects its civic as much as its religious role. It was declared a national monument (Bien de Interés Cultural) in 1931.