On an open plain near the Drava River in Pannonia, Theodosius planned to end the usurpation of Magnus Maximus. Maximus had other ideas and with loyal units from the west, he enrolled the aid of Rugian mercenaries to meet Theodosius and his reconstituted eastern army that now included Goths, Huns and Alans.
The road to Poetovium, flanked by rain sodden fields and woods offers a relatively open plain.
Maximus deployed the majority of his cavalry on the right intending to envelop the enemy line while his centre and left would hold the enemy at bay. The battle opened with the Rugian mercenaries positioned on the left.
Theodosius seeing the overwhelming number of cavalry facing his left, decided to send his light horse to delay their approach, the main assault would take place in the centre. To support the infantry, Theodosius positioned the clibanarii on their right with orders to keep pace with the infantry line.
The infantry lines clashed and the legions of Maximus gained the initial advantage. Elsewhere, the cavalry of Maximus had a difficult time of dispersing the enemy light horse, despite their superiority of number.
Driving the Imperial centre further back, the legions of Maximus were confronted by a second line with the Imperial banner among their ranks. Theodosius moved his second line forward to meet the enemy legions. On the Imperial right, the clibanarii destroyed the Rugian mercenaries. Maximus’ fate was sealed as Imperial archers put to flight a unit of auxilia and were now facing Maximus and his guard. It was time to leave..