Saint George's Church was probably founded in 1251. The date was proposed based on an Arabic inscription on a khachkar over the western door of the church yard. According to 13th century chronicler Hovhannes Erznkatsi, the church was built by Prince Umek of Karin.
The church was given to the Persian garrison by Safavid Shah Abbas I of Persia in 1616 and returned to the Armenian community in 1748 by King Heraclius II of Georgia. It was burnt when Persians sacked Tbilisi in 1795. The church was thoroughly restored in the 17th century, and then again in 1832 and 1881.
It became the seat of the Georgian Diocese of the Armenian Apostolic Church after the Vank Cathedral was demolished by Soviet authorities in the 1930s.
The most recent renovation of the church began in 2012 and was completed in 2015.
The church is built on a traditional plan of a partitioned, open cross with a rectangular perimeter. Like most of the churches in Tbilisi, it is built in brick. The outer walls of the church are covered with stucco.
Late 18th-century paintings by Hovnatan Hovnatanian decorate the church's interior. Between 1922 and 1923 Gevorg Bashinjaghian decorated the church's internal walls, the altar, and the walls in front of it, creating four large murals.
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.