The Roman Empire and Persians fought a series of wars over the centuries. Another conflict erupted in 295 with the Sassanid invasion of Armenia. The Persians scored an early success before the Romans responded with an invasion of their own. The war ended in a decisive Roman victory in 299 after two major battles.
In 293, Bahram III assumed the Sassanid throne. However, the nobility considered the young man weak and supported a usurper. Narseh murdered Bahram III in short order to assume power. Afterward, the new regime exchanged ambassadors with the Roman Empire. In the meantime, Narseh began to identify with Shapur I, the Sassanid emperor that skinned the Roman Emperor Valerian decades earlier. After consolidating power, Narseh hoped to skin another emperor and declared war on the Romans.
Diocletian was no Valerian, but Narseh's invasion seemed to surprise the Roman. The Sassanids attacked western Armenia first, then pivoted into Mesopotamia. In 297, the Persians scored a major victory in Syria. Diocletian forced the Roman general, Galerius, responsible for the defeat to walk for one mile ahead of the imperial retinue.
Diocletian punished, but neither removed nor executed, the general. Instead, the emperor reinforced Galerius. Meanwhile, Narseh's drive stalled, the Persians did not attempt to extend their gains, and the initiative fell to the Romans. Galerius swept into Mesopotamia in 298 forcing a Sassanid retreat into Armenia. The terrain proved disastrous for the Sassanid cavalry. Galerius scored twin victories over the Sassanids, captured the Persian treasury and Narseh's wife, children, and harem, claimed the enemy capital, and restored the territories lost earlier in the war.
The Romans won a complete and total victory over Narseh. The humiliated Persian
begged for the return of his family. Galerius scoffed at the request while
Diocletian dictated terms. The two sides concluded the Peace of Nisibis in 299.
The Sassanid Empire recognized Roman hegemony over Armenia and Iberia, Nisibis
would become the sole trade outlet between Rome and Persia, and the Romans
extended their influence in Mesopotamia. Diocletian also seized key strategic
outposts close to the Sassanid capital to keep an eye on the Persians and react
quickly if necessary. The treaty kept the peace between the two powers for over
The Sassanid Emperor Narseh experienced delusions of grandeur. He wished to lead
his forces to a dramatic victory over the Romans and relive the exploits of
Shapur I, the ruler that skinned a Roman emperor. However, the new Roman
emperor did not resemble his predecessor nor was the Roman Empire of the 290s in
the same weakened condition of the 260s. Inevitably, Narseh failed miserably and
Diocletian dictated a humiliating peace upon the Sassanid Empire.