Zosimus, New History 1.40

Zosimus (Greek Ζώσιμος): Early Byzantine, pagan author of a history of the Roman Empire, published in the first quarter of the sixth century CE.

The translation of Zosimus' New History offered here was printed in 1814 by W. Green and T. Chaplin in London, and was probably prepared by J. Davis of the Military Chronicle and Military Classics Office. The translator is anonymous. The text was found at Tertullian.org. The notes were added by Jona Lendering.

[1.40.1] While affairs were thus situated in the east, intelligence was brought to Gallienus, who was then occupied in the Scythian war, that Aurelian or Aureolus, who was commander of the cavalry posted in the neighborhood of Milan to watch the motions of Postumus, had formed some new design, and was ambitious to be emperor. Being alarmed at this he went immediately to Italy, leaving the command against the Scythians with Marcianus, a person of great experience in military affairs. 

[1.40.2] While he carried on the war with great ability, Gallienus, in his journey towards Italy, had a plot formed against him by Heraclianus, prefect of the court, who communicated his design to Claudius, in whom the chief management of affairs was vested. The design was to murder Gallienus. Having found a man very ready for such an undertaking, who commanded a troop of Dalmatians, he entrusted the action to him. 

[1.40.3] To effect it, the party stood by Gallienus at supper and informed him that some of the spies had brought intelligence that Aureolus and his army were close at hand. By this they considerably alarmed him. Calling immediately for his horse and arms, he mounted, ordering his men to follow him in their armor, and rode away without any attendance. Thus the captain finding him alone killed him.