Discovered in 2004 and the subject of excavations in 2005 and 2006, the ruins of the amphitheatre lie on two adjacent sites in the centre of modern Sofia.

[2] As evidenced by coin and ceramic findings, including a rare bronze medallion of Antinous, the amphitheatre was constructed on top of the theatre ruins in two stages during the late 3rd and early 4th century CE, under Roman emperors Diocletian (r. 284–305) and Constantine the Great (r.

[1][4] In the modern cityscape of Sofia, the ruins lie south of Knyaz Aleksandar Dondukov Boulevard, between the Goethe-Institut headquarters and the embassy of the United Kingdom.

[5] In July 2006, digging of the foundations of a National Electric Company office building in the vicinity[5] came across further parts of the arena.

It is freely accessible for tourists during the day, except on Mondays,[1] and includes a small expositions of coins and ceramics unearthed on the site.

In terms of architecture, the amphitheatre was comparable to the Arènes de Lutèce in modern Paris, France, and was designed for a maximum attendance of more than 20,000[2] up to around 25,000.

[4] The stand for high-ranking Roman officials lay in the southern section of the amphitheatre, near what is today the National Art Gallery.

Items discovered during the amphitheatre excavations include bear and boar bones, hundreds of bronze coins[2] and clay stones imprinted with the footprints of goats, dogs, and cats.