Constantine, thinking that Licinius was fleeing to Byzantium in order to retreat to his Asian base, headed to that direction, unintentionally placing Licinius between himself and his communication lines with the West.
It seemed that his aggressiveness had turned against him this time.
However, both belligerents had reasons to come to terms since Licinius was still in precarious position, so he sent a certain Mestrianus to negotiate with Constantine.
Even then, Constantine delayed the discussions until he was made sure that the outcome of the war was indeed uncertain.
A critical point might be when he received news of a sudden enemy raid that captured his baggage and the royal entourage.

According to the peace finalized at Serdica on 1 March 317 (a date chosen deliberately by Constantine because it was the anniversary of his father's elevation), Licinius recognised Constantine as his superior in government, ceded to him all European territories except for Thrace and deposed and executed Valens.
Constantine named himself and Licinius consuls while his two sons Crispus and  Constantine II as well as Licinius' son were appointed Caesars.
The peace lasted for about seven years.
Constantine, thinking that Licinius was fleeing to Byzantium in order to retreat to his Asian base, headed to that direction, unintentionally placing Licinius between himself and his communication lines with the West. It seemed that his aggressiveness had turned against him this time. However, both belligerents had reasons to come to terms since Licinius was still in precarious position, so he sent a certain Mestrianus to negotiate with Constantine. Even then, Constantine delayed the discussions until he was made sure that the outcome of the war was indeed uncertain. A critical point might be when he received news of a sudden enemy raid that captured his baggage and the royal entourage. 
According to the peace finalized at Serdica on 1 March 317 (a date chosen deliberately by Constantine because it was the anniversary of his father's elevation), Licinius recognised Constantine as his superior in government, ceded to him all European territories except for Thrace and deposed and executed Valens. Constantine named himself and Licinius consuls while his two sons Crispus and  Constantine II as well as Licinius' son were appointed Caesars. The peace lasted for about seven years.
Battle of Mardia