Galerius is reinforced, probably in the spring…
298 CE
Galerius is reinforced, probably in the spring of 298, by a new contingent collected from the empire's Danubian holdings.
Narseh does not advance from Armenia and Mesopotamia, leaving Galerius to lead the offensive in 298 with an attack on northern Mesopotamia via the mountains of Armenia.
Diocletian may or may not have been present to assist the campaign.
Narseh retreats to Armenia to fight Galerius' force, to Narseh's disadvantage: the rugged Armenian terrain is favorable to Roman infantry, but unfavorable to Sassanid cavalry.
Local aid gives Galerius the advantage of surprise over the Persian forces, and, in two successive battles somewhere near the Upper Tigris River, Galerius annihilates a much superior Persian force.
During the second encounter, Galerius captures a great deal of plunder, along with King Narseh’s harem and family.
Following up his advantage, he takes the city of Ctesiphon.