The Arch of Galerius (Greek: Αψίδα του Γαλερίου) 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.

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.

[3] In late 1864, when Frenchman Emmanuel Miller arrived in the city with the aim to remove and take to France the portico known as Las Incantadas the population of the city loudly objected, and the public outcry grew even more intense when false rumours spread that Miller also intended to dismantle and remove the Arch of Galerius as well; the arch was not touched at all or taken (but Las Incantadas was).

[5] 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 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).

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.

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.

[citation needed] Galerius' wife, Diocletian's daughter Valeria, is shown at his side, helping authenticate his connection to his predecessor.

The Rotunda stood empty for several decades until the Emperor Theodosius I ordered its conversion into a Christian church in the late fourth century.

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 surviving mosaics depict many organic forms such as a garland of fruit and evergreen plants that surrounded the lost image of Christ in the cupola.

[7] The presence of this evergreen suggests ideas of rebirth and by extension the Resurrection while the inclusion of various plants associated with all the four seasons could symbolize renewal and eternity.

In the strongly colored barrel vaults one panel displays a variety of fruits including grapes while another depicts a golden cross surrounded by many stylized flowers and acanthus leaves.