Danubian Legions and Parthian Wars

[Centurio]

I was looking at the map of Roman world in AD 117 and realized that after the conquest of Dacia, the province of Upper Moesia with its two legions (IV Flavia Firma and VII Claudia P.F.) lost its status of frontier province. What is a mystery to me, why Roman government used to sent Pannonian legio II Adiutrix to the East during Parthian wars of AD II instead of one of Upper Moesian legions, stationed in a rear province? Both Pannonias (Lower and Upper) remained frontier provinces and as Wilkes stated in his article legio IV Flavia arrived to Aquincum from Singidunum to replace II Adiutrix which was involved in Eastern wars of Lucius Verus and Septimius Severus. Why Emperors didn't send IV Flavia or VII Claudia directly from Moesia to the East? What explanation can be given to this decision?

[marka]

the legion may have been sent as a punishment.
it happened quite often later on with the troops of a defeated usurper or ones of doubtful loyalty.

the threat "from within" during the roman empire could be a lot more deadly than the barbarian threat.

[D B Campbell]

What is a mystery to me, why Roman government used to sent Pannonian legio II Adiutrix to the East during Parthian wars of AD II instead of one of Upper Moesian legions, stationed in a rear province? ... What explanation can be given to this decision?

There are so many factors that we are completely ignorant of, not least the changes of emperor and the differences that that may have made. Logically, we would expect a domino effect, where the nearest legions would be called upon, and those further away would shuffle along to fill the gap. Of course, this doesn't happen.

The repeated involvement of certain legions (you call attention to II Adiutrix; I Minervia is another) may indicate some kind of specialism ... or perceived specialism. Or there may be other factors at work. Remember, warfare meant the potential for glory, which every self-respecting Roman coveted. Only those legates involved in the fighting could hope to win renown, so there may have been favouritism at work, too. We can speculate, ... but we simply don't know. :wink: