The power struggles in Mediolanum due to Aureolus' revolt, the murder of Emperor Gallienus and the resulting confrontation between Aureolus and Claudius, who had been nominated as emperor by Gallienus on his death bed, had forced the Romans to denude the frontier of troops.

The Alamanni, who have been making incursions into Roman territory since the reign of Marcus Aurelius, have broken through the Roman frontier at the Danube and crossed the Alps in 268.

Claudius, having defeated and killed Aureolus in the Siege of Mediolanum, leads his army north, together with the remants of Aureolus' force, to confront the Germans.

The new emperor meets the Alamanni and Juthungi in battle at Lake Benacus (Lake Garda), in late autumn 268 (or early 269), inflicting so crushing a defeat on the enemy that only half their number manage to escape the battlefield alive.

Details of the battle are unknown but future emperor Aurelian certainly played a part.

After what will be described as a complete victory, Claudius assumes the title Germanicus Maximus.

Much of the German army had been slaughtered on the field with the remainder retreating beyond the bounds of the empire.

Claudius returns to Rome after the battle to attend to affairs of state.