Romanesque single-nave church oriented eastward, ending in a semicircular apse covered by a barrel vault reinforced by three transverse arches. It is built on a steep slope, raising the apse’s base. The apse connects to the nave through a pronounced presbytery bay and is constructed of large ashlar blocks arranged in very regular courses. A square bell tower stands attached to the south façade near the apse. The two entrances are on the north façade, heavily buttressed to support the thrust of the transverse arches. The tower’s masonry covers a twin-splayed window, suggesting the bell tower was built after the nave. The apse is decorated with Lombard arcading between lesenes. The “Castro Uliana” is documented from 919; between 1037 and 1040 the church of Sant Andreu was consecrated, and later abandoned when the settlement moved to current Oliana.