enclosing the central arch were re-used from Visigothic origins in the 7th century. On the outside of the church, it is worth noting the large number of buttresses (32) which seem in some cases to have a merely aesthetic function. Nearby this church is the Asturian Pre-Romanesque Information Centre, located in the old Norte de la Cobertoria Railway Station. Fourth period (866 to 910) This comprises the reign of Alfonso III, who came to the throne at the age of 18, on the death of his father, Ordoño I, marking the zenith of the kingdom of Asturias. Expansion against Islam led him to conquer Oporto and Coimbra in present-day Portugal, and he pushed the borders of the kingdom as far as the Mondego, repopulating Zamora, Simancas, Toro and the whole area known as Campos Góticos. The idea of the Asturian kingdom as a continuation of the Visigoths in Toledo was fully assumed, involving the obligation to re-conquer all the territory occupied by Muslims. This idea was reflected in the historical chronicles, such as the Crónica Albeldense, written in Oviedo in the year 881, which tells the history of the Gothic kingdom (Ordo Gentis gothorum), followed by the Asturian monarchy (Ordo Gothorum Obetensium fíegnum). The kingdom's moment of expansion and maturity was also reflected in a cultural revitalisation promoted from the court, involving architectural and artistic renewal. The kingdom's progressive expansion and increasing power also kindled the ambition of Alfonso III's three sons (García I, Ordoño II and Fruela II), who, encouraged by a number of noblemen, dispossessed the king and confined him in the town of Boiges (Boides valley, present-day Valdediós). Even so, they allowed him to lead a final campaign against the Muslims in Zamora, where he was victorious once more. He died on his return, in December of the year 910. Described in the chronicles as "Great King and Emperor" (Magnus Imperatore ImpemtorNoster),the king who had achieved the kingdom's greatest expansion and consolidation since it was founded by Pelayo, could not prevent his since from splitting it into three parts, Asturias, Galicia and Castile-León, meaning the disappearance of the kingdom of Asturias. San Salvador de Valdediós and Santo Adriano de Tuñón are the two churches built by this monarch, in addition to the Foncalada fountain (fonte incalata) in the centre of Oviedo, and the already-mentioned gold artefacts of the Victory Cross and the Agate box. The Church of