Ratiaria (or: Raetiaria, Retiaria, Reciaria, Razaria; Bulgarian: Рациария; Greek: Ραζαρία μητρόπολις; later named Colonia Ulpia Traiana Ratiaria) was a city founded by Moesi, a Daco-Thracian tribe, in 4th century BC, along the river Danube. The city had a gold mine in the vicinity, which was exploited by the Thracians.
Only during the principate of Augustus, the Romans conquered the region, which was organized in the province of Moesia. In 33/34 AD a road is linked between Viminacium and Ratiaria. The city was certainly less important than the near Sirmium, Viminacium and Naissus, but its location along the Danube limes made it a key point to station a legion. Legio IV Flavia Felix was based here at least until the conquest of Dacia (101-106 AD), together with the military fleet of Classis Moesica (during Vespasian).
It is unclear whether Aurelian or the Emperor Diocletian replaced Dacia Aureliana with two provinces, but by 285, there were two: – Dacia Mediterranea with its capital at Serdica and Dacia Ripensis, with its capital at Ratiaria. Later these two “Dacias” along with Dardania, Moesia Inferior, and Praevalitana constituted the Diocese of Dacia.
Famous individuals 
See also 
- AE 1911, 214; AE 1919, 81.
- Bury, p. 135. The date must be A.D. 283, and it is obvious that Aurelian set up the boundary stones, one of which Gaianus restored. There were, then, two Dacias when Diocletian came to the throne and, therefore, Mr. Fillow has inferred that we should read in our List: Dacia <Dacia>, that is presumably Dacia Ripensis and Dacia Mediterranea. Aurelian's Dacia mediterranea might have included Dardania, and Dardania, Mr. Fillow thinks, was split off as a distinct province by Diocletian.
|Wikimedia Commons has media related to: Dacian and Dacians|
- Bulgarian Archaeological Association - Excavations at Ratiaria
- Archaeological excavations of Ratiaria by the village of Archar
- Sarcophagus Ratiaria (Image)