Editing Licinius (section)

==Conflict with Constantine I==
{{See also|Civil wars of the Tetrarchy (306–324 AD)}}
In 316, a civil war erupted between Licinius and Constantine, in which Constantine used the pretext that Licinius was harbouring Senecio, whom Constantine accused of plotting to overthrow him.<ref name=Gibbon /> Constantine prevailed at the [[Battle of Cibalae]] in [[Pannonia]] (8 October 316).<ref name=DiMaio /> As a result of this defeat Licinius named [[Valerius Valens]] as his co-emperor (whom he originally intended to replace Constantine), only for Licinius to suffer a humiliating defeat on the plains in the [[Battle of Mardia]] (also known as the Battle of Campus Ardiensis) in [[Thrace]] which occurred either in late 316 or early 317. The two emperors were reconciled after these two battles and Licinius had his co-emperor Valens killed.<ref name=DiMaio />

Over the next seven years, the two imperial colleagues maintained an uneasy truce.<ref name=Gibbon /> Licinius kept himself busy with a campaign against the Sarmatians in 318,<ref name=DiMaio /> but temperatures rose again in 321 when Constantine pursued some Sarmatians, who had been ravaging some territory in his realm, across the Danube into what was technically Licinius's territory.<ref name=DiMaio /> When he repeated this with another invasion, this time by the [[Goths]] who were pillaging [[Thrace]] under their leader [[Rausimod]], Licinius complained that Constantine had broken the treaty between them.

Constantine wasted no time going on the offensive. Licinius's fleet of 350 ships was defeated by Constantine's fleet in 323. Then in 324, Constantine, tempted by the "advanced age and unpopular vices"<ref name="EB"/><ref name=Gibbon /> of his colleague, again declared war against him and having defeated his army of 165,000 men<ref>Grant p. 46</ref> at the [[battle of Adrianople (324)|Battle of Adrianople]] (3 July 324), succeeded in shutting him up within the walls of [[Byzantium]].<ref name="EB"/><ref name=DiMaio /> The defeat of the superior fleet of Licinius in the [[Battle of Hellespont|Battle of the Hellespont]] by [[Crispus]], Constantine's eldest son and [[Caesar (title)|Caesar]], compelled his withdrawal to [[Bithynia]], where a last stand was made; the [[Battle of Chrysopolis]], near [[Chalcedon]] (18 September),<ref name="EB">{{1911|wstitle=Licinius|volume=16|page=587|inline=1}}</ref> resulted in Licinius' final submission.<ref name=Gibbon /> In this conflict Licinius was supported by the Gothic prince [[Alica]]. Due to the intervention of Flavia Julia Constantia, Constantine's sister and also Licinius' wife, both Licinius and his co-emperor [[Martinian (emperor)|Martinian]] were initially spared, Licinius being imprisoned in [[Thessalonica]], Martinian in [[Cappadocia (Roman province)|Cappadocia]]; however, both former emperors were subsequently executed. After his defeat, Licinius attempted to regain power with Gothic support, but his plans were exposed, and he was sentenced to death. While attempting to flee to the Goths, Licinius was apprehended at [[Thessaloniki|Thessalonica]]. Constantine had him hanged, accusing him of conspiring to raise troops among the barbarians.<ref name=Gibbon /><ref>Grant, pp. 47–48</ref>