Sofia is the capital city of Bulgaria. It is located in the eponymous valley at the Vitosha Mountain foot in the country’s western parts. This large is established west of the Iskar river and has several mineral springs, such as the Sofia Central Mineral Bath. Being in the Balkans center, it is halfway between the Adriatic Sea and the Black Sea and nearest to the Aegean Sea.
Sofia’s history spans thousands of years from prehistoric days to modern times, during which the capital has been an industrial, commercial, economic, and cultural center in its territory and the Balkans.
Prehistoric days
Sofia was populated since at least the 30th millennium BCE. A Neolithic village around the National Art Gallery is recorded to the 3rd millennium BCE.
The oldest tribes who lived were the Thracian Tilataei. In the 500s BC, the region became part of a Thracia, the Odrysian kingdom.
In 339 BC Philip II of Macedon ravaged and destroyed the old settlement.
The Celtic clan Serdi gave their name to the city. The oldest mention of the town comes from Athenian writing from the 1st century BCE, attesting Astiu ton Serdon, i.e., the city of the Serdi. A local description and Dio Cassius reported that the Roman general Crassus defeated the Serdi and executed the captives.

Around 29 BCE, the Romans conquered Sofia was conquered.
It slowly became the most powerful Roman town of the province and became a municipium, or center of an administrative region, during Emperor Trajan’s reign (98-117) and was renamed Ulpia Serdica.
The city was destroyed and burnt in 170 by the Costoboci. This time, the city was restored with its first defensive walls between 176-180 under Marcus Aurelius, as proven by engravings above the gates.

The city grew again, as public baths, cult and cult administration, a civic basilica, and a large theatre were built. When Emperor Diocletian split the region of Dacia into Dacia Ripensis (on the Danube banks) and Dacia Mediterranea, Serdica became the capital of the latter.
In 268, a Gothic raid burned and ravaged parts of the city, including the abandoned theatre.
The city continued to grow and became a notable economic and political center. It became one of the first Roman cities where Christianity was officially recognized as a religion (under Galerius). A theater was built under Diocletian (284–305) and later under Constantine (306–337).

The Edict of Toleration was announced in 311 in Serdica by the Roman emperor Galerius, formally ending the Diocletianic oppression of Christianity. The Edict implicitly awarded Christianity the status of “religion licita,” worship accepted and recognized by the Roman Empire. It was the first Edict legalizing Christianity, preceding Milan’s Edict by two years.
Middle Age
Sofia first became a member of the First Bulgarian Empire during Khan Krum’s reign in 809. Afterward, it was identified by the Bulgarian name Sredets and grew into an administrative center and important fortress.
After several failed sieges, the city fell to the Byzantine Empire in 1018. In 1128, Sredets experienced a Magyar invasion as part of the Byzantine Empire, but in 1191 was once again included in the restored Bulgarian Empire at the time of Tsar Ivan Asen I after the Vlach-Bulgarian Rebellion.
From the 12th to the 13th century, Sofia was a thriving craft and trade center. It was ultimately renamed Sofia in 1376 after the Church of Sophia. However, it was called both “Sredets and “Sofia” until the 16th century, when the new name slowly replaced the old one.
During the Middle Ages, Sofia was known for its goldsmithing, significantly supported by mineral resources’ wealth in the neighboring hills. This is proven by the number of gold treasures excavated from antiquity.
Ottoman period

In 1385 Sofia was conquered and besieged by the Ottoman Empire during Murad I’s reign. Ottoman citizens from Anatolia joined the Bulgarian-speaking population during that period. Sofia saw the 1443 crusade of John Hunyadi and Władysław III of Varna, a frantic effort to drive out the Ottomans. The campaign failed, and many Sofia residents were imprisoned for their participation, especially those from the elite classes. Afterwards, Sofia became the capital of Rumelia, the territory that administered the Ottoman lands in the Balkans. During that time, Sofia was the most extensive import-export center in modern-day Bulgaria for the Ragusa Republic’s caravan trade.
19th and 20th centuries
Sofia was captured by Russian forces in 1878, during the Russo-Turkish War, 1877, and became the capital of Bulgaria’s self-governing Principality in 1879, which became the Kingdom of Bulgaria in 1908.
Most mosques in Sofia were destroyed in that war, seven of them removed in one night in December 1878 when a downpour masked the noise of the blasts arranged by Russian military engineers. Following the war, the great bulk of the Muslim population left Sofia.
In 1907, the Monument to the Tsar Liberator was launched on Tsar Osvoboditel Boulevard in Sofia.
In 1925, the worst act of terrorism in Bulgarian history, the St Nedelya Church attack, was carried out by the Bulgarian Communist Party, killing 150 and wounding another 500.