The Rotunda of Galerius is also known as the Greek Orthodox Church of Agios Georgios, and is informally called The Rotunda. It is one of the most glorious and famous landmarks of the city of Thessaloniki which has also been declared as a UNESCO World Heritage Site. It was built in 306 AD on the orders of the tetrarch Galerius, who was thought to have intended it to be his mausoleum. It was more likely intended to be a temple but is not known to what god it would have been dedicated. The Rotunda has a diameter of 24.5 m. Its walls are more than 6 m thick, which is why it has withstood Thessaloniki's earthquakes. The walls are interrupted by eight rectangular bays, with the south bay forming the entrance. A flat brick dome, 30 m high at the peak, crowns the cylindrical structure. In its original design, the dome of the Rotunda had an oculus, as does the Pantheon in Rome. The Rotunda was decorated by mosaics in at least two distinct periods between the 4th and the 6th centuries AD. Their creation was generally connected with sponsorships by emperos and high ranking secular and religious officials. They were works of unique artistic quallity, original iconography, and superb style which together with the mosaics of Rome and Ravena are among the masterpieces of Early Christian art. In addition they are considered to be the earliest mural mosaics in the Middle East, executed by a local mosaic workshop, They adorned the vaults over the recesses, the arched openings of the lunettes, and the dome. The decoration on the vault of the south recess gives the impression of a carpet: on the silver ground, around the gold cross in the center, are spread flowers, birds, stars and baskets of fruit. In the dome the remains of the richly decorated mosaic of the glory are rendered in bright colors. All that remains is the heads, hands and wings of three of the four angels. The representation of Christ in the centre is ruined. The zone underneath the dome is decorated with mosaics representing luxurious houses and portraits of saints.