Sarlio had been paid by King Hugh to cause unrest in Spoleto, to give cause for the removal of Anscar.
[1] Perhaps exceeding his instructions, Sarlio moved on an unspecified city, probably Spoleto, with six acies (units, literally "spearheads") of experienced troops.
He initially took the advice and sent messengers for reinforcements, but a certain Arcod—who is described as a Burgundian, like Sarlio—pressure him into assaulting Sarlio's camp.
Sarlio himself led from the rear, watching the battle from across a river, possibly the Tessino or Clitumno.
[1] When the first charge by the defenders was successful, Sarlio sent a further two acies into battle under Count Hatto, who had once supported Anscar.