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 the Sassanid Persians. About two-thirds 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 exposed on its southern side.
Location and description of the Arch
The Arch of Galerius
Arch of Galerius, stands on what is now Egnatia & Dimitrios Gounari Street. The arch was built in 298 to 299 AD and dedicated in 303 AD to celebrate the victory of the tetrarch Galerius over the Sassanid Persians and 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 (235m 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 (4 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
Galerius attacks Narses
The imperial family at the sacrifice of thanksgiving.
The tetrarchs arrayed in unison with a Victoria holding a victory wreath to the Augusti.
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.