 He eventually joined the Byzantine army to fight against them, becoming an important ally of both Emperor and Pope.After Faroald, the Lombard duke of Spoleto, captured Classis, the port of Ravenna, Droctulf recaptured it for the Empire in 575–76.He was briefly imprisoned (Paul refers to a "captivitas"), but was released to the Empire and served as the commander ("dux", duke) of the Byzantine post of Brescello (Reggio nell'Emilia), which guarded a bridge over the river Po leading to Classis, from around 584.