DACIA. — Under the Empire, this name denoted a vast region of Central Europe between Sarmatia and Germany, roughly bounded on the west by the Tisia (Theiss), on the south and southeast by the Danube, extending eastward to the lower course of the Tyras (Dniester) and the Carpathians.
The modern regions corresponding to it are Transylvania, Wallachia, and Moldavia. The inhabitants, the Dacians (Dai, Getae), were akin in race and language to the Thracians. Toward the end of the Roman Republic, King Burebista united many of their tribes into a single state, arousing concern due to his boldness to such an extent that Julius Caesar, governor of Cisalpine Gaul and Illyricum, seemed destined to turn his arms against him rather than toward the conquest of Transalpine Gaul. The danger to the Roman frontiers recurred a century later, when another energetic ruler, Decebalus, again held the Dacian tribes together.
During the reign of Domitian, the Romans fought repeatedly against the Dacians, not always with success, so that Trajan had to undertake two major campaigns that led to the complete subjugation of the country (in 107).
Reduced to a Roman province and provided with roads, military camps, and colonies, it did not, however, have very secure borders, so much so that as the barbarian pressure grew ever more severe throughout the 3rd century, Emperor Aurelian in 271 decided to withdraw the occupying troops and colonists to the south of the Danube, designating a part of the province of Moesia as Dacia, which was then subdivided into Dacia Ripensis along the river and Dacia Mediterranea around Sardica (Sofia). Within the borders of what had been the province of Dacia between 107 and 271, soldiers and colonists introduced various religions and cults, and epigraphic evidence is relatively abundant, with dedications to diverse Greco-Roman, Syrian, and Persian deities (including Mithras). Christianity must have penetrated there as well, but traces of it are scarce—far less abundant, for example, than in neighboring Scythia Minor on the Black Sea coast southeast of the Danube. Some sepulchral inscriptions are recorded at Napoca (Cluj, Kolozsvár), at Sardica, a sarcophagus in the Belgrade museum, relief crosses near Drobeta, a Christian lamp at Luciu, and a Constantinian monogram on gold bars found at Cefalva in Transylvania (CIL, III, 808). Even if one accepts, as St. Jerome does (Epist., 59), a preaching of St. Paul as far as Illyricum, and even if one grants the claims of the Church of Sirmium (Mitrovitza) to trace its origins to apostolic times, none of this would pertain to Dacia, which the Danube separates from Illyricum.
The new Dacia of Aurelian, that south of the Danube, had bishoprics in the 4th century, flourishing among them that of Sardica, where a council was held in 343, and that of Remesiana, made illustrious by the work of Bishop St. Nicetas (cf. the *carmen de Niceta* by St. Paulinus of Nola: the saint speaks of Dacia Mediterranea and Ripensis and calls the Dacians on the other bank "Getae").
In the time of Justinian, a bishop of Aquae is known in Dacia Ripensis, whose jurisdiction extended to places on the left bank of the Danube.