Arch of Galerius and Rotunda
The Arch of Galerius () or Kamara (Καμάρα) and the Rotunda (Ροτόντα) are neighbouring early 4th-century AD monuments in the city of Thessaloniki, in the region of Central Macedonia in northern Greece. History. The 4th-century Roman emperor Galerius commissioned these two structures as elements of an imperial precinct linked to his Thessaloniki palace. Archeologists have found substantial remains of the palace to the southwest. These three monumental structures were connected by a road that ran through the arch, which rose above the major east–west road of the city. At the crux of the  major axes of the city, the Arch of Galerius emphasized the power of the emperor and linked the monumental structures with the fabric of 4th-century Thessaloniki. The arch was composed of a masonry core faced with marble sculptural panels celebrating a victory over Narses (Narseh), the seventh emperor in the Sassanid Persian Empire, in 299 AD. About two-thirds of the arch is preserved. The Rotunda was a massive circular structure with a masonry core that had an oculus like the Pantheon in Rome. It has gone through multiple periods of use and modification as a polytheist temple, a  Christian basilica, a Muslim mosque, and again a Christian church (and archaeological site). A minaret is preserved from its use as a mosque, and ancient remains are displayed on its southern side. Location and description of the Arch. The Arch of Galerius stands on what is now the intersection of Egnatia and Dimitriou Gounari streets. Construction of the arch was spanned the years 298 and 299 AD; it was dedicated in 303 AD to celebrate the victory of the tetrarch Galerius over the Sassanid Persians at the Battle of Satala and the capture of their capital Ctesiphon in 298. The  structure was an octopylon (eight-pillared gateway) forming a triple arch that was built of a rubble masonry core faced first with brick and then with marble panels with sculptural relief. The central arched opening was 9.7 m wide and 12.5 m high, and the secondary openings on other side were 4.8 m wide and 6.5 m high. The central arch spanned the portion of the Via Egnatia (primary Roman road from Dyrrhacium to Byzantium) that passed through the city as a "decumanus" (east-west major street). A road connecting the Rotunda (125m northeast) with the Palace complex (235 m southwest) passed through the arch along its long axis. Only the northwestern three of the eight pillars and parts of the masonry cores of the arches above survive: i.e., the entire eastern side (four pillars) and the southernmost one of the western pillars are lost. Extensive consolidation with modern brick has been performed on the exposed masonry cores to protect the monument. The two pillars flanking the central arched passageway retain their sculpted marble slabs, which depict the wars of Galerius against the Persians in broadly panegyric terms. Sculptural program of the Arch. Understanding of the sculptural program of  the arch is limited by the loss of the majority of the marble panels, but the remains give an impression of the whole. Four vertically stacked registers of sculpted decoration were carved on each pillar, each separated by elaborate moldings. A label for the Tigris River indicates that there were likely labels on other representations as the builders deemed necessary. Artistic license was taken in the representations, for instance, the Caesar Galerius is shown in personal combat with the Sassanid Shah Narses in one of the panels; although they never met in battle. On the arch a mounted Galerius attacks  a similarly mounted Narses with a lance as an eagle bearing a victory wreath in its talons approaches Galerius. The Caesar sits securely on his rearing horse, while the Persian king appears nearly unhorsed. Terrified Persians cower under the hooves of the Caesar's horse in the chaos of battle. The panel expresses the power of the Caesar Galerius. The relief of the imperial family conjoined in a sacrifice of thanksgiving owes its distant prototype to the Augustan reliefs on the "Ara Pacis" in Rome. Galerius' wife, Diocletian's daughter Valeria, is shown at his side, helping authenticate his connection  to his predecessor. Here as elsewhere all the faces have been carefully chiselled off, whether as "damnatio memoriae" or in later cultural intolerance of images. In another panel, the tetrarchs are all arrayed in the toga as a "Victoria" holds a victory wreath out to the heads of the two "Augusti". A third panel celebrates the unity of the tetrarchy, with a depiction of the tetrarchs standing together; the depersonalized manner in which the tetrarchs are portrayed is reminiscent of the schematic statues of the tetrarchs in porphyry at St. Mark's Basilica in Venice. Only Galerius is dressed in  armor, and he makes the offering upon the altar. What remains of the arch asserts the glory of the tetrarchy and the prominence of Galerius within that system. The arch celebrates the Roman Empire as part of Galerius' victory over the Sassanid king. Galerius is also pictured on his horse at the right, while attacking a Sassanid guard. Rotunda of Galerius. Location and description of the Rotunda. The Rotunda of Galerius is 125m northeast of the Arch of Galerius at 40°37'59.77"N, 22°57'9.77"E. It is also known (by its consecration and use) as the Greek Orthodox  Church of "Agios Georgios", and is informally called the Church of the Rotunda (or simply The Rotunda). The cylindrical structure was built in 306 AD on the orders of the tetrarch Galerius, who was thought to have intended it to be his mausoleum. 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 west 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. Uses of the Rotunda. After Galerius's death in 311, he was buried at Felix Romuliana (Gamzigrad) near Zajecar, Serbia. The Rotunda stood empty for several decades until the Emperor Theodosius I ordered its conversion into a Christian church in the late fourth century. The church was embellished with very high quality mosaics. Only fragments have survived of the original decoration, for example, a band depicting saints with hands raised in prayer, in front of complex architectural fantasies. The building was used as a church  ("Church of Asomaton or Archangelon") for over 1,200 years until the city fell to the Ottomans. In 1590 it was converted into a mosque, called the Mosque of Suleyman Hortaji Effendi, and a minaret was added to the structure. It was used as a mosque until 1912, when the Greeks captured the city during the Balkan War. Greek Orthodox officials reconsecrated the structure as a church, and they left the minaret. The structure was damaged during an earthquake in 1978 but was subsequently restored. , the minaret was still being stabilized with scaffolding. The building is now a historical monument under  the Ephorate of Byzantine Antiquities of the Greek Ministry of Culture, although the Greek Orthodox Church has access to the monument for various festivities some days of the year (as Church of Saint George). The Rotunda is the oldest of Thessaloniki's churches. Some Greek publications claim it is the oldest Christian church in the world, although there are competitors for that title. It is the most important surviving example of a church from the early Christian period of the Greek-speaking part of the Roman Empire.