Sofia was originally a Thracian settlement called Serdica, named after the Thracian tribe Serdi. Around 500 BC another tribe settled in the region, the Odrysi, known as an ethnos with their own kingdom. For a short period during the 4th century BC, the city was ruled by Philip of Macedon and his son Alexander the Great.
Around AD 29, Sofia was conquered by the Romans and renamed Ulpia Serdica. It became a municipium, or centre of an administrative region, during the reign of Emperor Trajan (98-117).
The first written mention of Serdica was made by Ptolemy (around 100 AD).
The city expanded, as turrets, protective walls, public baths, administrative and cult buildings, a civic basilica and a large amphitheatre called Bouleutherion, were built. When Emperor Diocletian divided the province of Dacia into Dacia Ripensis (on the banks of the Danube) and Dacia Mediterranea, Serdica became the capital of Dacia Mediterranea. The city subsequently expanded for a century and a half, which caused Constantine the Great to call it "my Rome".
Serdica was of moderate size, but magnificent as an urban concept of planning and architecture, with abundant amusements and an active social life. It flourished during the reign of Byzantine Emperor Justinian I, when it was surrounded with great fortress walls whose remnants can still be seen today.
The city was destroyed by the Huns in 447 but was rebuilt by Justinian and renamed Triaditsa.
Sof?a es la capital y la ciudad m?s grande de la Rep?blica de Bulgaria, con una poblaci?n de 1.270.450 habitantes (lo que la convierte en la 14? mayor ciudad de la Uni?n Europea), y alrededor de 1.380.406 en su ?rea metropolitana, la Provincia Capital. . Se localiza en la regi?n oeste de Bulgaria, a los pies del Macizo Vitosha, y es el centro administrativo, cultural, econ?mico y educativo de la naci?n.
Siendo una de las capitales m?s antiguas de Europa, la historia de Sof?a se remonta al siglo VIII adC, cuando los tracios establecieron un asentamiento en la zona. Sof?a ha tenido varios nombres en los diferentes periodos de su existencia, y hoy en d?a a?n se pueden ver remanentes de la milenaria historia de la ciudad al lado de los atractivos tur?sticos modernos.