The history of Dacian warfare spans from c. 10th century BC up to the 2nd century AD in the region defined by Ancient Greek and Latin historians as Dacia. It concerns the armed conflicts of the Dacian tribes and their kingdoms in the Balkans. Apart from conflicts between Dacians and neighboring nations and tribes, numerous wars were recorded among Dacians too.
The Dacians fought amongst each other but were later united first under Burebista and later under Decebalus. Despite this after the death of Burebista at 44 BC they had been split by a civil war.
The two punitive expeditions mounted as a border defense against raids of Moesia from Dacia in 86-87 AD ordered by the Emperor Titus Flavius Domitianus (Domitian) in 87 AD, and 88 AD. The first expedition was an unmitigated disaster, and the second achieved a peace, seen as unfavorable and shameful by many in Rome.
Trajan's Dacian Wars. The two campaigns of conquest ordered or led by the Emperor Trajan in 101-102 AD, and 105-106 AD from Moesia across the Danube north into Dacia. Trajan's forces were successful in both cases, reducing Dacia to client state status in the first, and taking the territory over in the second. These wars involved no less than 13 legions.
The Dacian tribes were part of the greater Thracian family of peoples. They established a highly militarized society and, during the periods when the tribes were united under one king (82 -44 BC, 86-106 AD), posed a major threat to the Roman provinces of Lower Danube. Dacia was conquered (except for the Free Dacians) and transformed into a Roman province in 106 after a long, hard war.