Sestertius - Trebonianus Gallus P M S COL VIM AN XII, Viminacium

Viminacium, the legionary fortress-city on the Danube in Moesia Superior, operated its own civic bronze coinage from 239 AD under Gordian III — an unusual privilege granted to relatively few Balkan cities. The local era dating system stamped on these coins, marking years from that 239 foundation, is one of the more reliable chronological anchors for the turbulent reigns of the soldier-emperors. Trebonianus Gallus himself rose to power in Moesia, acclaimed by his own troops after the death of Decius at Abrittus in 251, which likely explains the continued vitality of the Viminacium mint under his brief rule.