Europe 298: Galerius’ invasion of Persia
After his failure at Carrhae, Galerius gathered a stronger force and returned to face the Persians in Armenia. In 298 he surprised and decisively defeated Shah Narseh near Satala, capturing his wife, harem, treasury, and much of his court. Galerius then invaded Persia itself and captured the capital Ctesiphon. The following year, at the Peace of Nisibis, Narseh agreed to cede territory to the Romans and restore the Kingdom of Armenia. It would be another four decades before the two empires would fight again.
The Agri Decumates was lost to the Romans in c.262, regained by Aurelian and Probus in 275–8, and lost again sometime between 290 and 310. The losses here seem not so much due to any rise in power of the local Alemanni tribe, but Roman internal division. When rival Roman factions controlled Gaul and Raetia, as was the case in 262–274 and 306, the limes of the Agri Decumates were no longer defensible and had to be abandoned.
Capitals of the First Tetrarchy
Officially, Rome remained the capital of the Roman Empire throughout the Tetrarchy. In practice, the real capital was wherever Diocletian’s court—and to a lesser degree, that of the other tetrarchs—resided. This varied considerably in the East, where Diocletian was initially based at Sirmium, in the Balkans, then joined Galerius in Antioch, before finally swapping places with his Caesar altogether by taking command at Antioch and Nicomedia while Galerius took charge in the Balkans (at Thessalonica and then Serdica). In the West the situation was less fluid: except for providing some brief support on the Rhine and a few years spent in Spain and Africa, Maximian remained based at Mediolanum, in Italy; his Caesar, Constantius, was largely based at Augusta Treverorum, in Gaul.
298 Battle of Satala▲
After his defeat at Carrhae, Galerius gathered new troops from Illyricum and Moesia and, in the winter of 297/298, marched on Armenia to confront Shah Narseh of Persia again. Here, from the Roman base of Satala and supported by the exiled Armenian king Tiridates III, Galerius launched a surprise attack on the nearby Persian camp and utterly defeated the Persian army. In the rout, the Romans captured Narseh’s wife, harem, children, treasury, and much of his court. Narseh himself narrowly escaped.
298–299 Galerius’ invasion of Persia▲
Following his victory at Satala, Galerius and his Armenian allies swept the Persians from Armenia. He then marched through Media Atropatene and Adiabene to return to Roman Mesopotamia and recover Nisibis by the end of September 298, winning many victories along the way. From here, Galerius pushed down the Tigris to capture the Persian capital Ctesiphon and bring the war to an end.
??–Sep 298 Diocletian’s Nubian Campaign▲
After restoring order and implementing reforms in Alexandria, Diocletian marched south along the Nile to Nubia, where he made peace with the Nobatae and Blemmyes tribes. Realizing that the region south of the city of Elephantine cost far more to defend than it provided in revenue, he granted it to the Nobatae and shifted the border north to nearby Philae, where he constructed a strong fortress and a temple to cater for both nations. Diocletian then further placated the tribes by agreeing to pay them both an annual gold stipend to end their raiding.
298? Julianus vs Maximian▲
During the reign of Maximian in the West, perhaps in around 298 when all four tetrarchs were engaged on the frontiers of the empire, a man named Julianus proclaimed himself emperor in Italy. The authorities acted quickly, possibly aided by the return of Maximian, who had arrived back in Italy from his African campaigns in late 298. They soon besieged the usurper in a city and, when they breached the walls, Julianus killed himself by leaping into a fire.