[citation needed] The threat was reduced when dynastic struggles in Dacia led to a division into four (or five, depending on the source) separately governed tribal states after Burebista died in 44 BC.

In 29 BC, Augustus sent several punitive expeditions into Dacia led by Marcus Licinius Crassus Dives, the consul of the prior year, that inflicted heavy casualties and apparently killed three of their five kings.

[1]: 9–10 In the winter of 85/86 AD[2] after 116 years of relative peace along the Roman frontier, King Duras led by General Diurpaneus, swarmed over the frozen Danube and pillaged Moesia.

To replenish their forces and greatly strengthen the Roman army in this territory, the Legio IV Flavia Felix from Dalmatia and two more legions, the I and II Adiutrix, were moved to Moesia from the western provinces.

Domitian promoted as new commander in chief, Tettius Julianus, who, having crossed the Danube, probably at the legionary fortress of Viminacium, managed in the following autumn to reach the plain of Caransebeș, in front of the Iron Gates, perhaps after an enveloping approach conducted in several columns, and not without great difficulties due to the continuous attacks of the Dacians.

[17] For the remainder of Domitian's reign Dacia remained a relatively peaceful client kingdom, but Decebalus used the Roman money to fortify his defences.

Trajan continued Domitian's policy and added two more units to the auxiliary forces of Upper Moesia, using the buildup of troops for his Dacian wars.