Fluidr / David&Bonnie's "Bulgaria" set

The Church of St George is an Early Christian red brick rotunda that is considered the oldest building in Sofia, Bulgaria. It is situated amid remains of the ancient town of Serdica.

Built by the Romans in the 4th century, it is a cylindrical domed structure built on a square base. It is believed to have been built on the site of a pagan temple. The church is famous for the 12th-, 13th- and 14th-century frescoes inside the central dome. Three layers of frescoes have been discovered, the earliest dating back to the 10th century. Magnificent frescoes of 22 prophets over 2 metres tall crown the dome. Painted over during the Ottoman period, when the building was used as a mosque, these frescoes were only uncovered and restored in the 20th century.

The church is at a level a few metres below the modern streets of the capital. It is considered to be the oldest preserved building in the city, built at a time when Sofia was the residence of the emperors Galerius and Constantine the Great.

The church is part of a larger archaeological complex. Behind the apse, there are ancient ruins: a section of a Roman street with preserved drainage, foundations of a large basilica, probably a public building, and some smaller buildings. One of the buildings had been equipped with hypocaust and the tiles lifting the floor can be seen today. Experts define it as one of the most beautiful buildings in the so-called "Constantine district" of Serdika-Sredets, where the palace of Emperor Constantine the Great, was situated.

The Rotunda was built of red bricks and has a complex symmetry. At the centre, there is a domed rotunda room with a circular plan on a square base with semicircular niches in the corners. Since the 4th century, it has been used for christening (baptising) ceremonies. The dome rises to 13.7 m from the floor.

Despite its small size, the church is similar to the Rotunda of Thessaloniki in Greece. Carrying the spirit of the early Christian era and Bulgarian medieval culture, St. George has a huge cultural value. It is subject to extensive research and legitimate interest not only among the Orthodox and Catholic church communities and prominent science and culture figures, but it attracts many pilgrims and ordinary tourists.