Editing Bahram V (section)

===War with Rome===
{{main|Roman–Sasanian War of 421–422}}
[[File:Roman-Persian Frontier, 5th century.png|thumb|The Roman-Sasanian frontier]]

At the urging of the Zoroastrian priests and the [[House of Suren|Surenid]] minister (''[[wuzurg framadar]]'') [[Mihr Narseh]], Bahram V began his reign with a systematic persecution of the [[Christianity in Iran|Christians]].{{sfn|Pourshariati|2008|p=62}}{{sfn|Greatrex|Lieu|2002|pp=36–43}} The persecuted Christians fled to Roman territory, and were welcomed by the bishop of Constantinople, [[Archbishop Atticus of Constantinople|Atticus]], who informed the Emperor of the persecution. The Eastern Roman Emperor [[Theodosius II]] was at the time deeply influenced by his religious sister [[Pulcheria]], and had become more and more interested in Christianity.{{sfn|Greatrex|Lieu|2002|pp=36–43}} The Roman-Sasanian relationship already had some friction. The Sasanians had hired some Roman gold-diggers, but now refused to send them back; furthermore, they had also seized the properties of Roman merchants. So, when Sasanian ambassadors reached the Roman court to ask for the fugitives, Theodosius chose to break the peace and [[Roman–Sasanian War (421–422)|declare war]], rather than giving them back.{{sfn|Greatrex|Lieu|2002|pp=36–43}}

In the year 421, the Romans sent their general [[Ardabur (consul 427)|Ardaburius]] with an extensive contingent into Armenia. The Iranian general Narses engaged Ardaburius in battle, but was defeated and forced to retreat. Narses planned to attack [[Mesopotamia (Roman province)|Mesopotamia]], a Roman province that had been left unguarded, and moved there, but Ardaburius foresaw his enemy's plan and intercepted him there.{{sfn|Greatrex|Lieu|2002|pp=38–39}} Ardaburius shortly received reinforcements and put the fortress of [[Nisibis]] under siege, but withdrew in the face of an advancing army under Bahram, who in turn besieged Theodosiopolis (probably [[Theodosiopolis (Osroene)|Theodosiopolis]] in [[Osroene]]).{{sfn|Greatrex|Lieu|2002|pp=36–43}}

The peace treaty that ended the war (422) was negotiated by the ''[[magister officiorum]]'' Helio. It returned everything to the situation before the war (''[[status quo ante bellum]]''). Both parts agreed to reject Arab defectors of the other part, as well as to guarantee liberty of religion in their territories.{{sfn|Greatrex|Lieu|2002|pp=36–43}} Furthermore, the Romans also agreed to pay the Iranians for the protection of the pass at the Sasanian city of [[Derbent]] in the Caucasus.{{sfn|Frye|1983|p=145}} Since the peace treaty of 387, Iran and Rome had agreed that both empires were obligated to cooperate in the defense of the Caucasus against nomadic attacks.{{sfn|Shayegan|2013|p=809}} While the Romans saw this payment as political subsidies, the Iranians saw it as tribute, which proved that Rome was the deputy of Iran.{{sfn|Payne|2015|p=298}}