Durostorum became an important military center of the Roman province of Moesia, and grew into a city at the time of Marcus Aurelius. Durostorum became the seat of a Christian bishopric and a center of Christianity in the region. Auxentius was expelled from Durostorum by an edict of Theodosius depriving Arian bishops in 383, and took refuge at Milan where he became embroiled in controversy with St Ambrose. The Roman general Flavius Aëtius was born in the town in 396. When the Roman Empire split into the Eastern and Western empires, the town (known as , in Byzantine Greek) became part of the Eastern (Byzantine) Empire. As part of the Bulgarian Empire Durostolon was known as "Drastar" in Medieval times.