The Dacian Wars ( 101–102 , 105–106 ) were two military campaigns fought Hostile_encounter between the Roman Empire and Dacia during Emperor Trajan 's rule .

The conflicts were triggered Causation by the constant Dacian threat on the Danubian province of Moesia and also by the increasing need for resources of the economy of the Empire .

Emperor Trajan recommenced Process_start hostilities against Dacia and , following an uncertain number of battles , defeated Conquering the Dacian king Decebalus in the Second Battle of Tapae in 101 .

With Trajan 's troops pressing Self_motion towards the Dacian capital Sarmizegetusa Regia , Decebalus once more sought terms .

In response Trajan again marched Self_motion into Dacia , besieging Besieging the Dacian capital in the Siege of Sarmizegetusa , and razing Destroying it .