Zosimus, New History 2.28

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.

[2.28.1] But Licinius being besieged by Constantine at Nicomedia also, knew not what to do, being sensible that he had not an army equal to engage. Going, therefore, out of the city, he submitted himself to Constantine, and brought him the purple robe, proclaiming him his emperor and lord, and intreating pardon for what was past. 

[2.28.2] He presumed that he certainly should escape with life, because Constantine had sworn to his wifenote that he would spare him. But Constantine delivered Martinianus to the guards that they might put him to death, and sent Licinius to Thessalonica, as if he were to live there in security. However, he afterwards broke his oath, which was usual with Constantine, and caused him to be executed.