Editing Galerius (section)

===Invasion, counterinvasion===
In 294, [[Narseh]], a son of [[Shapur I]], who had been passed over for the Sassanid succession, came into power in Persia. Narseh probably moved to eliminate [[Bahram III]], a young man installed by a noble named Vahunam in the wake of Bahram II's death in 293.{{sfn|Potter|2004|p=292}}<ref name = "Williams Diocletian">{{citation | last = Williams | title = Diocletian}}</ref>{{rp |69}} In early 294, Narseh sent Diocletian the customary package of gifts, but within Persia, he was destroying every trace of his immediate predecessors, erasing their names from public monuments. He sought to identify himself with the warlike reigns of [[Ardashir I|Ardashir]] (r. 226–241) and [[Shapur I|Shapur]] (r. 241–272), who had sacked Roman Antioch and captured Emperor [[Valerian (emperor)|Valerian]].<ref name = "Williams Diocletian" />{{rp |69–70}}

In 295 or 296, Narseh declared war on Rome. He appears to have first invaded western Armenia, retaking the lands delivered to Tiridates in the peace of 287. He occupied the lands there until the following year.{{sfn|Potter|2004|p=292}}{{sfn|Southern|2001|p=149}}{{sfn|Barnes|1981|p=17}}<ref>Ammianus Marcellinus 23.5.11.</ref> The historian Ammianus Marcellinus, circa 320–395, is the only source detailing the initial invasion of Armenia.{{sfn|Potter|2004|p=651–652}} Southern (1999, 149) dates the invasion to 295; Barnes (1982, 17, 293) mentions an earlier, unsuccessful invasion by Narseh based on the fact that the title ''Persici Maximi'' was given to all four emperors; Odahl (2004, 59) concurs with Barnes and suggests that Saracen princes in the Syrian desert collaborated with Narseh's invasion. Narseh then moved south into Roman Mesopotamia, where he inflicted [[Battle of Carrhae (296)|a severe defeat]] on Galerius, then commander of the eastern forces, in the region between Carrhae ([[Harran]], Turkey) and Callinicum ([[Raqqa]], Syria).{{sfn|Barnes|1981|p=17}} Diocletian may or may not have been present at the battle,{{sfn|Potter|2004|p=652}} but  presented himself soon afterwards at Antioch, issuing an official version of events which placed all the blame for the affair upon Galerius. In Antioch, Diocletian forced Galerius to walk a mile in advance of his imperial cart while still clad in the purple robes of an emperor.{{sfn|Potter|2004|p=292–293}}{{sfn|Barnes|1981|p=17}} [[David Stone Potter]] reads a symbolic message in the display: the loss at Carrhae was due not to the failings of the empire's soldiers, but to the failings of their commander, and Galerius' failures would not be accepted.{{sfn|Potter|2004|p=293}} Another scholar, Roger Rees, suggests that Galerius' position at the head of the caravan was merely the conventional organization of an imperial progression, designed to show a ''Caesar''<nowiki/>'s deference to his ''Augustus''.{{sfn|Rees|2004|p=14}}

[[File:Arch-of-Galerius-1.jpg|right|thumb|Detail of Galerius attacking [[Narseh]] on the [[Arch and Tomb of Galerius#Arch of Galerius|Arch of Galerius]] at [[Thessaloniki]], [[Greece]], the city where Galerius carried out most of his administrative actions.{{sfn|Southern|2001|p=151}}]]

Galerius' army was reinforced probably in the spring of 298 by new contingents collected from the empire's Danubian holdings.{{sfn|Barnes|1981|p=18}} Narseh did not advance from Armenia and Mesopotamia leaving Galerius to lead the offensive in 298 with an attack on northern Mesopotamia via Armenia.{{sfn|Potter|2004|p=293}} Diocletian may or may not have been present to assist the campaign.<ref>Lactantius (''DMP'' 9.6) derides Diocletian for his absence from the front; Southern (1999, 151, 335–336), on the basis of a dating of the African campaigns one year earlier than that given by Barnes, places him at Galerius' southern flank. Southern sees the Persian campaign progressing along the lines of [[Marcus Aurelius]]' (r. 161–180) earlier, unsuccessful [[Roman–Parthian War of 161–66|Parthian campaign]], which also had an emperor manning the southern flank.</ref> Narseh retreated to Armenia to fight Galerius' force, putting himself at a disadvantage; the rugged Armenian terrain was favorable to Roman infantry, but not to Sassanid cavalry. Local aid gave Galerius the advantage of surprise over the Persian forces, and he defeated Narseh in two successive battles.{{sfn|Potter|2004|p=293}}{{sfn|Barnes|1981|p=18}} During the second encounter, the [[Battle of Satala (298)|Battle of Satala]] in 298, Roman forces seized Narseh's camp, his treasury, his harem, and his wife.{{sfn|Potter|2004|p=293}}{{sfn|Barnes|1981|p=18}} Narseh's wife would live out the remainder of the war in Daphne, a suburb of Antioch, serving as a constant reminder to the Persians of the Roman victory.{{sfn|Potter|2004|p=293}}

Galerius advanced into [[Media (region)|Media]] and [[Adiabene]], winning continuous victories, most prominently near [[Erzurum|Theodosiopolis]] (Erzurum),{{sfn|Southern|2001|p=151}} and securing [[Nusaybin|Nisibis]] (Nusaybin) before 1 October  298. The historian Timothy Barnes argues that he moved down the [[Tigris]], taking [[Ctesiphon]]. Barnes' main argument for this is that Eusebius' biography of Constantine mentions that the later emperor had seen the ruins of [[Babylon]] according to this work.{{sfn|Barnes|1981|p=18}} Patricia Southern also argues that he took Ctesiphon based on the uncertainty of the location where the seizure of Narseh's wife and harem took place. However, no source ever specifically claims that Ctesiphon was sacked and many other historians argue Diocletian prevented him from moving further into Sasanian territory.{{sfn|Southern|2001|p=150}}<ref>{{cite book |last1=Dignas |first1=Beate |last2=Winter |first2=Engelbert |title=Rome and Persia in Late Antiquity: Neighbours and Rivals |date=13 September 2007 |publisher=Cambridge University Press |isbn=978-0-521-84925-8 |pages=29–30 |url=https://books.google.com/books?id=MG2hqcRDvJgC&pg=PA51 |language=en}}</ref>