St. John Apostle and Evangelist (Iglesia de San Juan Apóstol y Evangelista) is a Roman Catholic Asturian pre-Romanesque church situated in Santianes de Pravia. The church contains a foundation stone in the form of a letter labyrinth ('Silo Princeps Fecit') that records the 8th-century founding of the church by King Silo of Asturias. The inscription Silo princeps fecit singularly combined in fifteen horizontal lines and nineteen perpendicular columns of letters. The T forms the beginning and the end of the first and last line in consequence of which the name Silo is not to be found till the eighth line and the S which begins it is exactly in the centre of that line and of the tenth column thus the name is in the shape of a cross as the letters above below and on each side of the S form the word Silo.
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.