Zosimus, New History 2.55

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 ZosimusNew 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.

[2.55.1] After these occurrences, the whole empire being now in the hands of Constantius, he began to be more arrogant than before, and could not conduct himself with any moderation in his prosperity. The state-informers, with which such men are usually surrounded, and which are designed for the ruin of those that are in prosperity, were augmented. These sycophants, when they attempted to effect the downfal of a noble in hopes of sharing his wealth or honors, contrived some false accusation against him. 

[2.55.2] This was the practice in the time of Constantius. Spies of this description, who made the eunuchs of the court their accomplices, flocked about Constantius, and persuaded him that his cousin german Gallus, who was a caesar, was not satisfied with that honor, but wished to be emperor. They so far convinced him of the truth of this charge, that they made him resolve upon the destruction of Gallus. The contrivers of this design were Dynamius and Picentius, men of obscure condition, who endeavored to raise themselves by such evil practises. 

[2.55.3] Lampadius also, the prefect of the court, was in the conspiracy, being a person who wished to engross more of the emperor's favor than any other. Constantius listened to those false insinuations, and Gallus was sent for, knowing nothing of what was intended against him. As soon as he arrived, Constantius first degraded him from the dignity of caesar, and, having reduced him to private station, delivered him to the public  executioners to be put to death. This was not the first time that Constantius imbrued his hands in the blood of his relations, but only one other in addition to many former.