[1] The battle occurred during the Roman campaigns under Augustus to conquer the northern Alps and regions south of the Danube river.

During the last phase of the campaigns in the spring of 15 BC two Roman armies under Drusus and Tiberius set out to subdue Raetia.

Drusus' army started from northern Italy crossing the Alps and moving towards the present-day city of Augsburg.

According to Strabon, the Vindelici, a group of Celtic tribes native to the area, attacked the Roman vessels on the lake in a naval engagement but were defeated.

Cassius Dio only tells of the construction of transport ships and does not mention any naval engagement.