Santa María del Naranco was built by request of Ramiro I in the IX century, on the slope of the Mount Naranco and it has an Asturian Pre-romanesque style.
It is a unique building without a clear-cut purpose (palace, church, royal pavilion, royal hall, etc.) with rectangular ground plan divided in two floors connected by an external stairway. It is a rectangular building with a gable roof raised over a stone base that, from the outside, seems to have three floors.
On the inside, the lower floor has a central hall with two chambers on both sides, conforming the superior balconies. The central hall is domed and the lateral ones have a wooden ceiling. The upper floor has the central or noble hall similar to the lower floor.
Ramiro I in the year 842 also requested to build the pre-romanesque church of San Miguel de Lillo, which together with Santa María del Naranco, make up what is known as the Mount Naranco Pre-Romanesque. Church of San Miguel de Lillo originally had a three naves ground plan but nowadays only one third of the original building is preserved. There is a gallery at the west end of the nave, above the old porch, and surrounded on both sides by small chambers. Most of it is made with ashlar, with beautiful lattices carved in stone. The prominent sculptures are very remarkable, especially the jambs near the entrance.
Both monuments were declared World Heritage Site in 1985 by Unesco.
Further info on http://www.prerromanicoasturiano.es