The Baptistery of San Giovanni ad Fontes is a religious edifice in Lomello. An example of Romanesque-Lombard architecture, it is annexed to the basilica of Santa Maria Maggiore, another early Middle Ages structure.
The baptistery has a typical cross plan, but in the interior the central part forms an octagon, over which is a dome of the same shape. The interior is wholly plastered, and can be accessed from two portals. The baptistery has, on the east-west axis, an overall length of 16 m.
The main element is the baptismal font, dating to the 7th-8th centuries.
The baptistery has an elevation of 13 m and is entirely built of brickworks, parts of which date to the 5th-6th centuries. The dome is a later addition (c. 10th century), and was built using less precious materials.
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.