Licinius, on the other hand, had espoused paganism more and more openly in recent years, rescinding the Edict of Milan and attacking the church in order to seize its wealth for the building of the army with which he planned to destroy his brother wearer of the purple. To this end, he had developed a weapon whose extent he had been able to keep largely secret a vast fleet recruited from the maritime countries under his rule. At the Hellespont, the mouth of the waterway separating Europe from Asia, he now assembled more than three hundred and fifty ships of war under the command of an admiral named Amandus.
Constantine reacted to the knowledge that the coming conflict would be fought both on land and sea with two swift maneuvers. At Thessalonica, near the head of the Grecian Sea, he ordered that work be carried on night and day in the shipyards to build a fleet of two hundred war galleys and more than a thousand transports. In the meantime, lest Licinius attack the vital shipyards with his superior fleet and cripple this phase of the war, Constantine hastily prepared for a campaign on land designed to keep his opponent busy.
Licinius, however, countered by attacking, seeking to throw Constantine off balance before he could marshal enough land and sea forces for a combined pincers operation against Byzantium, whose fortifications had been rebuilt since the city had fallen to Maximin Daia so easily some ten years ago. Hurriedly mobilizing to meet this new threat, Constantine sent word for Crispus and Dacius to bring as many of the regular legions from Gaul as could be spared, leaving Crocus with a small force to parry any attack across the Rhine by the ever watchful Germanic tribes. From Italy, he also brought the legions ordinarily stationed there, adding them to his
Hardbitten veterans
Army of Illyricum, a force of hardbitten veterans of the campaign against the Goths.
It was a warm June day when Crispus and Dacius, at the head of a small but seasoned army from Gaul, marched into the camp on the plains before the city of Hadrianopolis, where Licinius had chosen to make his stand. Constantine greeted the two warmly and led them to a hill overlooking the area where the crucial battle would soon be fought.