This is alist of knowngovernors of the trans-DanubianRoman province of Dacia, referred to asDacia Traiana. Created in AD 106 by theRoman emperorTrajan after the final defeat ofDecebalus'Dacian kingdom, it was originally a single province under the nameDacia, governed by aLegatus Augusti pro praetore. In 118,Hadrian reorganised the province, abandoning some territory in the east and relabelling the provinceDacia Superior. At the same time he splitMoesia Inferior, with the territory north of theDanube renamed asDacia Inferior. In 123, Hadrian created a third Dacian province,Dacia Porolissensis, fashioning it out of territory from the northern portion ofDacia Superior.
Antoninus Pius undertook the next reorganisation in 158.Dacia Superior was renamedDacia Apulensis,Dacia Inferior was transformed intoDacia Malvensis, whileDacia Porolissensis remained as it was. During all these transformations,Dacia Superior/Dacia Apulensis was governed by aconsular legate, while the other two provinces were under the command of praesidial procurators.
Then in 166, the pressures building along the Danube frontier forced the new emperorMarcus Aurelius to reorganise the province once again. This time, he set up an overarching province which fused the three provinces into one, calledTres Daciae, commanded by a consular legate. However, the three provinces still remained as separate entities, each one governed by a praesidial procurator, who then reported to the proconsular governor. Apart from a brief period during theMarcomannic Wars when the province was temporarily split into three due to an emergency situation,Tres Daciae retained this structure untilAurelian abandoned the province in 271.
