Thracian & RomanSofia & Western Bulgaria

Serdica, the Roman City Beneath Today's Sofia

Serdica is the Roman city that stood on the site of today's Sofia, and its excavated gates, walls and other remains can be seen in the heart of the Bulgarian capital. It was a provincial capital, the birthplace of emperors and the place where a famous edict of toleration was issued in 311. It makes a fascinating, free-flowing walk through two thousand years of layered history.

Emperor Constantine reportedly called it “my Rome” and even considered making it his capital instead of Constantinople. Today Serdica lies under the pavements and underpasses of Sofia.

WhereCentral Sofia, the capital of Bulgaria

TypeRoman and late antique city with fortress walls, gates and public buildings

Best forAncient history fans and urban explorers who enjoy finding Roman layers inside a modern city

Getting thereIn the heart of Sofia; the remains are spread through the centre, so a walking visit works well

The history of Serdica

The Celtic tribe of the Serdi gave the city its name. The earliest mention comes from an Athenian inscription of the first century BCE that speaks of the “city of the Serdi”, and the Roman general Crassus is recorded as having defeated the tribe. The Romans took the place in the late first century BCE, after stubborn resistance. Under Emperor Trajan (98–117) it became a municipium, a self-governing city, and was renamed Ulpia Serdica; this is probably when its fortification began in earnest.

In 170 the Costoboci burnt the city. It was rebuilt between 176 and 180 under Marcus Aurelius and his son Commodus, this time with its first defensive walls: a rectangle of roughly 340 by 560 metres, about 17.5 hectares, with round and triangular towers and four gates, each flanked by double-tower bastions. A building inscription found at the western gate records the work. The city soon outgrew its walls and expanded with public baths, administrative and cult buildings, a civic basilica and a large theatre. When Emperor Diocletian divided Dacia, Serdica became capital of Dacia Mediterranea, and the emperors Aurelian and Galerius were born there. A Gothic raid in 268 burned parts of the city, including the theatre.

Serdica's great moment came in the fourth century. In 311 Galerius issued the Edict of Serdica, an edict of toleration that ended the Diocletianic persecution of Christians and gave Christianity the status of a recognised religion, two years before the Edict of Milan. Constantine the Great stayed here for long periods, is remembered for saying “Serdica is my Rome”, and is said to have considered making it the capital of his empire instead of Constantinople. Under him the city grew to the north with a second outer wall enclosing about 85 more hectares, and an amphitheatre was built over the remains of the older theatre. Around 343 a church council met here. Eight horrea, or warehouses, found in the south-western quarter suggest that Serdica was a regional supply centre linked to the Danube.

Serdica was devastated by the Huns in 447, and the Emperor Justinian rebuilt it in the sixth century, renaming it Triaditsa. Justinian's engineers raised and thickened the walls and added new triangular towers, and the gate bastions changed from horseshoe to pentagonal shape. On 9 April 809, Easter Sunday, the citizens opened the gates to the Bulgarian khan Krum and the city joined Bulgaria; the old claim that Krum razed it is described by Bulgarian archaeologists as a strong exaggeration. The walls were gradually flattened, mostly in the fourteenth and fifteenth centuries, and only low fragments survived into the early years of the modern Bulgarian capital before disappearing.

The ancient city lay buried until modern construction work began to bring it back. In 1969 the building of an underpass in front of what was then the Party House led to the first significant restoration and display of part of the fortress. Today the remains include the Complex of Ancient Serdica, the eastern and western gates, sections of the walls, thermal baths, a bridge over the river near Lions' Bridge, the fourth-century church of Saint George Rotunda, the amphitheatre and the tombs and basilicas beneath Saint Sophia Church.

Curious facts about Serdica

The Edict of Serdica of 311 came two years before the Edict of Milan; it offered conditional tolerance, while Milan dropped the condition about not disturbing order.
Constantine the Great is remembered for the phrase “Sardica mea Roma est”, meaning “Serdica is my Rome”.
The emperors Aurelian and Galerius were both born in Serdica.
The walls once rose around ten metres above the ground, with towers reaching fourteen metres.
Eight Roman horrea (warehouses) found within the walls hint that the city supplied the army on the Danube.
A peak on Livingston Island in Antarctica, Serdica Peak, is named after the city, and Serdica is also a titular see of the Roman Catholic Church.

Tours near Serdica

Experiences in the area that you can book online with Viator:

Half Day Tour around Sofia and the mountains with Thermal Spa

★ 5 (47 reviews) · 6 h

See details ›

ATV Off Road Tour Near Sofia Guided Quad Bike Experience

★ 5 (28 reviews) · 1.5 h

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Plovdiv, Asen's Fortress and Bachkovo Monastery small group tour with pickup

★ 5 (27 reviews) · 9 h

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Full-day Rila Monastery, Stob Pyramids and St Ivan Rilski Cave from Sofia

★ 5 (24 reviews) · 6 h

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Visiting Serdica: what to expect

The remains are scattered across central Sofia rather than gathered in a single enclosure, so allow time to walk between them.
The eastern gate of late antique Serdica can be seen in the underpass at Largo, where a building-inscription block from the northern gate is also displayed.
Part of the western gate is visible below street level in the courtyard of the new Catholic cathedral.
Nearby sights include the amphitheatre of Serdica, the Saint George Rotunda and Saint Sophia Church. Check the current opening hours before you go.
Explanatory material on the ancient city is available online in the form of a virtual guide linked from Wikipedia.

Opening hours, access and conditions can change. Check before you go.

Map: where Serdica is

Photos of Serdica

Questions

What was Serdica?

Serdica was the Roman city that stood on the site of today's Sofia. It became a provincial capital and an important political and economic centre.

Where can I see Serdica in Sofia today?

Remains are on display across the centre, including the eastern gate in the Largo underpass, sections of the walls, the thermal baths, the amphitheatre and the Saint George Rotunda.

Why is Serdica important to Christianity?

In 311 the emperor Galerius issued the Edict of Serdica here, an edict of toleration that ended the persecution of Christians. A church council also met in the city around 343.

Did Constantine really want to make Serdica his capital?

He is remembered for saying “Serdica is my Rome” and is said to have considered making it his capital instead of Constantinople, though that plan never came about.

Which emperors were born in Serdica?

Aurelian and Galerius were both born there.

How big was Roman Serdica?

The first fortress built in 176–180 covered roughly 17.5 hectares. Under Constantine the walled area grew to the north by about 85 hectares.