Serdica: Roman town, modern Sofia.
- Thracian town, named after the original inhabitants, the Serdi
- After 342/341 BCE: briefly occupied by Philip II and Alexander the Great
- 29 BCE: occupied by the Romans
- Rank of municipium during the reign of Trajan (r.98-117): Municipium Ulpia Serdica
- Diocletian: capital of Dacia Mediterranea
- 311 Galerius ends the Diocletianic Persecution of Christianity.
- 343 Council of Serdica (site of Byzantine church St Sofia)
- 447 sacked by the Huns
- Justinian: new wall, renamed Triaditsa
- Byzantine until early ninth century
- City wall