Roman emperor Trajan made Dacia a province after conquering it in 106 CE.
Trajan fought two major wars against the Dacian king Decebalus, in 101–102 and 105–106 CE. Roman forces crossed the Danube, captured the Dacian capital Sarmizegetusa, and forced Decebalus to take his own life. Trajan then organized much of the conquered territory as the Roman province of Dacia.
The conquest gave Rome valuable gold mines and extended imperial power north of the Danube. It also inspired Trajan’s Column in Rome, whose spiral relief shows scenes from the campaigns. The column is an important visual source, although its artistic scenes were designed to celebrate imperial victory rather than provide a neutral modern-style record.
Roman control of Dacia did not last permanently. Emperor Aurelian withdrew the Roman administration and army from the province around 271–275 CE, although Roman influence and population remained important in the region.