Zosimus, New History 4.01
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.
[4.1.1] In the preceding book I have related how affairs were conducted until the death of Jovian, after whom Valentinian was appointed emperor. I have now to state, that while Valentinian was on his journey towards Constantinople, he was seized with a distemper, which increased his natural choleric temper to a degree of cruelty, and even to madness, so that he falsely suspected his sickness to proceed from some charm or poison which Julian's friends had prepared for him through malice. Accusations to that effect were drawn up against some distinguished persons, which were set aside by the discretion of Sallustius, who still was prefect of the court.
[4.1.2] After his distemper abated, he proceeded from Nicaea to Constantinople. The army and his friends in that city advised him to chuse an associate in the empire, that if occasion should require, he might have some one to assist him, and prevent their again suffering as at the death of Julian. He complied with their advice, and after consideration, selected his brother Valens, whom he thought most likely to prove faithful to him. He declared him associate in the empire. While they resided at Constantinople, all who were enemies to the friends of Julian continually suggested at court, that certain persons had a design against the emperor, and incited the populace likewise to spread the rumor.