After co-emperor Constans had been assassinated in 350, Servatius was sent to the Roman emperor Constantius II in Edessa, the capital of Armenian Mesopotamia, as an envoy of the usurper Magnentius to represent the late Constans as an unworthy tyrant and oppressor, in the hope of obtaining Constantius' recognition of Magnentius as co-ruler. The mission failed and the resulting civil war ended with the death of Magnentius in 353. The mission can be seen as a sign of the high standing of Servatius. In 359, at the Council of Rimini, Sulpicius Severus reports that Servatius again eloquently denounced Arianism.