The church of the Holy Savior of Valdediós (Iglesia de San Salvador de Valdediós) stands in the Boides valley (Villaviciosa), the place where Alfonso III of Asturias was detained when he was dispossessed by his sons, and where there used to be an old convent governed by the Benedictine Order, substituted in the 13th century by the Cistercians. The church known as the 'Bishops' Chapel' was consecrated on 16 September 893, with seven bishops in attendance.
The church stands on a classic basilica ground plan with a triple sanctuary, separating the central nave from the side aisles with four semicircular arches. At the western end, there are three enclosures, the central one used as an access vestibule, and two located on the left and right which may have been used to house pilgrims. The vault over the central nave, like the one over the apses, is barreled with a brick ceiling and decorated with al fresco wall painting, alternating a variety of geometric designs.
The royal tribune is located above the vestibule, separate from the area intended for the congregation (spatium fidelium) in the central nave, and this from the area devoted to the liturgy by iron grilles, now disappeared. Particular elements of this church include the covered gallery annexed to the southern facade at a later date or Royal Portico, the 50 cm square columns on the central naves arches, the triple-arched window open in the central apse, and the room above it, exclusively accessed from the exterior by a window which here has two openings, compared with the habitual three.
References:The Church of St Donatus name refers to Donatus of Zadar, who began construction on this church in the 9th century and ended it on the northeastern part of the Roman forum. It is the largest Pre-Romanesque building in Croatia.
The beginning of the building of the church was placed to the second half of the 8th century, and it is supposed to have been completed in the 9th century. The Zadar bishop and diplomat Donat (8th and 9th centuries) is credited with the building of the church. He led the representations of the Dalmatian cities to Constantinople and Charles the Great, which is why this church bears slight resemblance to Charlemagne's court chapels, especially the one in Aachen, and also to the Basilica of San Vitale in Ravenna. It belongs to the Pre-Romanesque architectural period.
The circular church, formerly domed, is 27 m high and is characterised by simplicity and technical primitivism.