Sardinia was conquered by the Romans of the East under Emperor Justinian I in 534 AD. An expedition led by Belisarius defeated the Vandals and Cagliari entered the Byzantine administrative system as the seat of the ἄρχων (archon), the provincial governor, an imperial official in charge of the whole of Sardinia (Σαρδηνία) and subject to the Exarchate of Africa. During the Gothic War, which raged in the peninsula, Goths occupied the city for a short time before it was given back into Byzantine hands. In 599 AD, the fleet of the Lombard Agilulfo raided and plundered the coasts of Cagliari, but was finally repulsed by local militias.