A few minutes' walk from Santa María del Naranco on the same hillside, San Miguel de Lillo was built as Ramiro I's palace chapel in the mid-9th century. The original building was considerably larger, but a partial collapse left only the western third standing. What survives is still extraordinary: the carved stone reliefs on the door jambs depict scenes from Roman circus games, and the interior preserves fragments of Byzantine-influenced wall paintings.
Visit it together with Santa María del Naranco on a single joint ticket. The setting on Monte Naranco is lovely, with views down over the city and the Asturian countryside. The interpretation centre between the two churches has useful context on pre-Romanesque Asturias.