The church of St Mary at Mount Naranco (Spanish: Iglesia de Santa María del Naranco) (Asturian: Ilesia de Santa María'l Narancu) is a Roman Catholic Asturian pre-Romanesque Asturian architecture church on the slope of Mount Naranco situated 3 km from Oviedo, northern Spain. Ramiro I of Asturias ordered it to be built as a royal palace as part of a larger complex that also incorporated the nearby church of San Miguel de Lillo, 100 meters away. It was completed in 848. Its structural features, such as the barrel vault - with transverse ribs corresponding one-to-one with contraforts at the exterior, make it a clear precursor of the Romanesque construction. The exterior decorations, as well as the use of stilted arches mark the intended verticality of the composition. It was converted into a church at the end of the 13th century. It was declared a World Heritage Site by UNESCO in December 1985.