Throughout the 1st century, Roman policy dictated that threats from neighbouring nations and provinces were to be contained promptly. Dacia had been on the Roman agenda since before the days of
Julius Caesar when the Dacians defeated a Roman army at the
Battle of Histria.
Domitian's Dacian War had re-established peace with Dacia in 89 AD. However, the Dacian king
Decebalus used the Roman annual subsidy of 8 million sesterces and craftsmen in trades devoted to both peace and war, and war machines intended to defend the empire's borders to fortify his own defences instead. Despite some co-operation on the diplomatic front with Domitian, Decebalus continued to oppose Rome. At the time, Rome was suffering from economic difficulties largely brought on by military invasions throughout Europe and in part due to a low gold content in Roman money as directed by Emperor
Nero. Confirmed rumors of Dacian
gold and other valuable trade resources inflamed the conflict, as did the Dacians' defiant behaviour, as they were "unbowed and unbroken". However, other pressing reasons motivated them to action. Researchers estimate that only ten percent of barbarians such as Spanish and Gallic warriors had access to swords, usually the nobility. By contrast Dacia had rich resources of iron and copper and were prolific metal workers. A large percentage of Dacians owned swords, greatly reducing Rome's military advantage. Dacia sported 250,000 potential combatants, enough to enable an invasion. It was allied to several of its neighbours and on friendly terms with others that Rome considered enemies. Rome had no concrete defense policy and would not have been able to sustain a war of defense. As such, the new Emperor
Trajan, himself an experienced soldier and tactician, began preparing for war. That Dacia was considered a substantial threat can be seen by the fact that Trajan withdrew troops from other borders leaving them dangerously undermanned. == Trajan's First War ==