Zosimus, New History 2.25
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.
[2.25.1] Meantime Constantine continued intent upon the siege, and raised a mound of equal height with the wall, on which he placed wooden towers that overlooked the wall, from which his soldiers shot those who defended it, in order that he might with greater security bring battering rams and other engines of war near it. By these means he thought himself sure to take the city. At which Licinius, being terrified, and not knowing how to act, resolved to leave Byzantium, and the weaker part of his army therein, and to take with him only such men as were fit for active service, and had given proofs of their attachment to himself, and to hasten without delay to Chalcedon in Bithynia.
[2.25.2] He flattered himself that another army might be raised in Asia, which would enable him again to contend with his adversary. Arriving therefore at Chalcedon, and, having appointed Martinianus to the command of the court guards, whom the Romans call Magister officiorum, his associate in this dangerous enterprize, he declared him caesar, and sent him with an army to Lampsacus, to hinder the passage of the enemy from Thrace into the Hellespont. He posted his own men on the hills and passes about Chalcedon.