Rotunda of Galerius

The oldest monument in Thessaloniki, the Rotunda is a massive round building that was first a Roman temple, then a Christian church, then a mosque. Its walls are more than 6 meters (20 feet) thick, which is one reason why it has withstood Thessaloniki’s earthquakes. The cylindrical structure was built in 306 as part of a large palace complex on the orders of Roman emperor Galerius. It was either intended to be his mausoleum or somewhat more likely as a temple. The building was used as a church for over 1,200 years until the city fell to the Ottomans. In 1590 the Church of Agios Georgios was converted into a mosque. Fortunately, the mosaics that survived until then were not harmed further by this conversion; they were simply painted over. After serving three religions, the Rotunda is now a museum