According to an inscription of his in Susa, the control of the region is considered to have been Artabanus's. Elsewhere, Vologases VI's coins found in Seleucia show his control over the land. In Rome, Caracalla rose to power after the death of Septimius Severus, his father. Although the information about the contest between Artabanus and Vologases is trace, the Latin sources say that Caracalla gave special attention to the internal contest of Parthians and reported the disruption of the Parthians' status to the Roman Senate. Knowledge about the civil war in the Parthian Empire might have encouraged "the idea of a military conquest" in Caracalla and stimulated him towards successes larger than those of his father's (Septimius Severus) in fighting the Parthians. At the time while Emperor Caracalla had already been formulating a plan to start a new war with the Parthians, he sent a request for extradition of two fugitives, a philosopher named Antiochus and an unknown man called Tiridates, to Vologases searching for an excuse to start a war in 214 or early 215; Vologases returned the two fugitives; but Caracalla invaded Armenia anyway.