The Chapel of Santiago or St James the Greater (aka the Capilla de Arriba) is built, according to legend, over the chamber of St Turibius in which were hidden the relics now preserved in the Holy Chamber in Oviedo Cathedral. Like the Chapel of Mary Magdalene, it dates from late medieval times.
It has an octagonal ground plan and a semi-circular apse. The so-called Hermit's Cave is located on one side preceded by a straight bay. The entire construction is masonry, the outside being reinforced by buttresses. There are small bays in the wall. The doorway protrudes from the building. This has a semi-circular voussoir arch. The interior is covered by rib vaulting that rests on the buttresses. The apse is covered with a barrel vault in its straight section and a dome in the semi-circular section. The side area of the Hermit's Cave is also vaulted. Inside it conserves an altar table and traces of murals.
The Chapel of Santiago was restored in 1986 and 1989 by the Regional Ministry of Education, Culture and Sports.
