Zosimus, New History 2.20
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.
[2.20.1] Next day they agreed on a truce, and entered into an alliance with each other, on condition that Constantine should possess Illyricum and all the nations westward, and that Licinius should have Thrace and the east; but that Valens, whom Licinius had made caesar, should be put to death, because be was said to be the author of all the mischief which had happened.
[2.20.2] Having done this, and sworn on both sides to observe the conditions, Constantine conferred the rank and title of caesar on Crispus, his son by a concubine called Minervina, who was as yet but a youth, and on Constantine, who was born but a few days before at Arelate. At the same time Licinianus, the son of Licinius, who was twenty months of age, was declared caesar. Thus ended the second war.