Immediately after he succeeded to Friuli, Lupus invaded Grado with a body of cavalry and plundered the city, then proceeding to Aquileia, where he stole the treasures of the Patriarchate.
When King Grimoald went south to rescue his son Romuald and the Duchy of Benevento from the invasion of the Byzantine Emperor Constans II, he put Lupus in charge of Pavia.
Grimoald promptly asked the Khagan of the Avars to attack Friuli in order to prevent a civil war in Italy.
Fighting lasted for four days at Flovius,[1] during which Lupus held his own for three, taking much booty and slaughtering many men, before his own losses and the arrival of Avar reinforcements forced his army to retreat.
Lupus' son Arnefrit claimed Friuli on his father's death, but was unseated by Grimoald.