Santa Cruz de Cangas de Onís is a small Roman Catholic chapel in Cangas de Onís, the first capital of the Kingdom of Asturias. It was founded on an artificial mound (a pagan dolmen) by Favila, second king of Asturias, and his queen, Froiliuba. It was begun in 737 and consecrated that same year on 27 October according to its original foundation stone, which has been called the first literary monument of the Reconquista.
Santa Cruz originally housed the Cruz de la Victoria, an oak cross supposedly carried by Pelagius, Favila's father, at the Battle of Covadonga. It was probably the first church constructed after the Islamic invasion of Spain in 711.
The church was completely rebuilt on two occasions. First in 1632 and again after its destruction in the Spanish Civil War (1936). Then, local authorities decided to uncover the dolmen beneath it, which had been obscured by a church since the fourth century, when the first chapel was put up on that site. Of the original building only the foundation stone survives.
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.