San Andrés church was built in the quarter of Ajates (a suburb of mediaeval origin in which the main trade was masonry) in the second quarter of the 12th century. It was made in Caleno granite (very typical of the Romanesque style in the town) and is set according to liturgical criteria with an upper end with three apses that correspond to the three naves in the interior; it does not have a transept nave. The protruding central apse is of particular interest thanks to the number of figures and capitals and the closed arches on the straight section of the upper end, which stand as a unique example of Romanesque capitals. The variety of icons on the interior and exterior capitals is the largest of all of Ávila's Romanesque buildings and is associated with the Masters of León. The central apse has two absidioles of a smaller size and a plainer composition.
The upper end is covered with decreasing stepped vaults: barrel vaults along the straight section and calotte vaults along the curved section. The southern absidiole has a lobulated arch used as the entrance and unparalleled in any other church in Ávila at the time.
The south front has a semi-circular window and the keystone of the semi-circular archivolt contains a Chi Rho which, fitted in the 13th century, is considered as the first of its kind in the town. The tower stands next to the western side, built onto the nave during or after the 14th century.
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.