Editing Diocletian (section)

===Maximian made Augustus===
[[File:5 Aurei, Diocletian and Maximianus Herculius, Elephantenquadriga, Rome, 287 AD - Bode-Museum - DSC02724.JPG|thumb|Diocletian and Maximian on an aureus (AD&nbsp;287)]]
Maximian's campaigns were not proceeding as smoothly. The Bagaudae had been easily suppressed, but [[Carausius]], the man he had put in charge of operations against [[Saxons|Saxon]] and [[Franks|Frankish]] [[Piracy|pirates]] on the [[Saxon Shore]], had, according to literary sources, begun keeping the goods seized from the pirates for himself. Maximian issued a death warrant for his larcenous subordinate. Carausius fled the Continent, proclaimed himself emperor, and agitated Britain and northwestern Gaul into open revolt against Maximian and Diocletian.{{sfnm|1a1=Barnes|1y=1981|1pp=6–7|2a1=CAH|2pp=70–71|3a1=Potter|3y=2005|3pp=283–284|4a1=Southern|4y=2001|4pp=137–141|5a1=Williams|5y=1985|5pp=45–47}}

Far more probable, according to the archaeological evidence, is that Carausius had held some important military post in Britain,{{sfn|Southern|2001|p=138}} already had a firm basis of power in Britain and Northern Gaul, and profited from the lack of legitimacy of the central government.{{sfn|Potter|2005|p=284}} Carausius strove to have his legitimacy as a junior emperor acknowledged by Diocletian: in his coinage, he extolled the "concord" between him and the central power. One bronze piece from 290 read PAX AVGGG, "the Peace of the three Augusti"; on the other side, it showed Carausius together with Diocletian and Maximian, with the caption CARAVSIVS ET FRATRES SVI, "Carausius & his brothers".{{sfn|Southern|2001|pp=138, 140}}<ref>{{cite web|author=Stephen J. Murray|year=2021|url=http://www.dot-domesday.me.uk/empires2.htm|title=New Empires|website=From Dot To Domesday – British History|access-date=20 January 2023|archive-date=14 October 2021|archive-url=https://web.archive.org/web/20211014181832/http://www.dot-domesday.me.uk/empires2.htm|url-status=live}}</ref> Diocletian could not allow a breakaway regional usurper following in [[Postumus]]'s footprints to enter, of his own accord, the imperial college.{{sfn|Williams|1985|pp=61–62}}

Spurred by the crisis, on 1 April 286,{{sfnm|1a1=Barnes|1y=1981|1pp=6–7|2a1=CAH|2p=69|3a1=Potter|3y=2005|3p=282|4a1=Southern|4y=2001|4pp=141–142|5a1=Williams|5y=1985|5pp=47–48}}{{refn|name=AUG|The chronology of Maximian's appointment as co-ruler is somewhat uncertain.{{sfnm|1a1=Corcoran|1y=2006|1p=40|2a1=Southern|2y=2001|2p=142}} Some argue that Maximian was appointed ''Augustus'' without ever holding the office of ''Caesar''.{{sfn|Southern|2001|p=142, "It has also been suggested that Maximian became Augustus at the very beginning of Diocletian’s reign. The chronology is not established  beyond doubt"}} 1 April 286, the date given by the 5th-century ''[https://archive.org/details/chronicaminorasa09momm/page/229/mode/1up Consularia Constantinopolitana]'', is the most common date used in modern histories for Maximian's ''[[dies imperii]]''.{{sfnm|1a1=Barnes|1y=1981|1pp=6–7|2a1=CAH|2p=69|3a1=Potter|3y=2005|3p=282|4a1=Southern|4y=2001|4pp=141–142|5a1=Williams|5y=1985|5pp=47–48}} A document dated 31 March 286 already shows Diocletian and Maximian as joint emperors. The ''CAH'' dates the assumption of the Augustan title to 1 March 286.{{sfn|CAH|p=69; following ''[[Berliner griechische Urkunden|BGU]]'' 4.1090.34}} According to a recent view, Maximian was appointed ''Augustus'' (without ever being ''Caesar'') on or around 13 December 285.{{sfnm|1a1=Burgess|1y=2023|2a1=Nixon|2a2=Rodgers |2y=2023|2pp=44-51}}|group="Note"}} Maximian took up the title of ''Augustus'' (emperor).{{sfnm|1a1=Barnes|1y=1981|1p=7|2a1=Bleckmann|2y=2006|3a1=Corcoran|3y=2006|3p=40|4a1=Potter|4y=2005|4p=282|5a1=Southern|5y=2001|5pp=141–142|6a1=Williams|6y=1985|6p=48}} Unusually, Diocletian could not have been present to witness it. It has even been suggested that Maximian usurped the title and was only later recognized by Diocletian in hopes of avoiding civil war.{{sfn|Potter|2005|p=649}} This suggestion is unpopular, as it is clear that Diocletian meant for Maximian to act with a certain amount of independence.{{sfnm|1a1=Potter|1y=2005|1p=282|2a1=Williams|2y=1985|2p=49}} It may be posited that Diocletian felt the need to bind Maximian closer to him, by making him his empowered associate, to avoid the possibility of him striking some sort of deal with Carausius.{{sfn|Southern|2001|p=141}}
[[File:Rare Carausius Denarius.jpg|left|thumb|[[Carausius]], rebel emperor of [[Roman Britain|Britain]]. Most of the evidence for his reign comes from his coinage, which was of generally fine quality.{{sfn|Southern|2001|p=140}}]]
Maximian realized that he could not immediately suppress the rogue commander, so in 287 he campaigned against tribes beyond the [[Rhine]] instead.{{sfnm|1a1=Barnes|1y=1981|1p=7|2a1=CAH|2p=71|3a1=Corcoran|3y=2006|3p=40}} As Carausius was allied to the Franks, Maximian's campaigns could be seen as an effort to deny him a basis of support on the mainland.{{sfn|Williams|1985|p=62}} The following spring, as Maximian prepared a fleet for an expedition against Carausius, Diocletian returned from the East to meet Maximian. The two emperors agreed on a joint campaign against the [[Alamanni]]. Diocletian invaded Germania through Raetia while Maximian progressed from Mainz. Each burned crops and food supplies as he went, destroying the Germans' means of sustenance.<ref>{{cite book|last=Rees|first=Roger|title=Layers of Loyalty in Latin Panegyric|year=2002|location=Oxford |publisher=Oxford University Press|isbn=978-0-19-924918-3|doi=10.1093/acprof:oso/9780199249183.001.0001}}</ref>{{sfnm|1a1=Southern|1y=2001|1pp=142–143|2a1=Williams|2y=1985|2p=50}} The two men added territory to the empire and allowed Maximian to continue preparations against Carausius without further disturbance.{{sfnm|1a1=Barnes|1y=1981|1p=7|2a1=Corcoran|2y=2006|2p=40|3a1=Southern|3y=2001|3p=143}} On his return to the East, Diocletian managed what was probably another rapid campaign against the resurgent Sarmatians. No details survive, but surviving inscriptions indicate that Diocletian took the title ''Sarmaticus Maximus'' after 289.{{sfnm|1a1=Barnes|1y=1982|1p=255|2a1=Southern|2y=2001|2p=144}}

In the East, Diocletian engaged in diplomacy with desert tribes in the regions between Rome and Persia. He might have been attempting to persuade them to ally themselves with Rome, thus reviving the old, Rome-friendly, [[Palmyra|Palmyrene]] [[sphere of influence]],{{sfn|Potter|2005|p=285}} or to reduce the frequency of their incursions.{{sfn|Williams|1985|p=63}} No details survive for these events.{{sfn|Southern|2001|p=144}} Some of the princes of these states were Persian client kings, a disturbing fact for the Romans in light of increasing tensions with the Sassanids.{{sfn|Williams|1985|p=78}} In the West, Maximian lost the fleet built in 288 and 289, probably in the early spring of 290. The [[panegyric|panegyrist]] who refers to the loss suggests that its cause was a storm,<ref>''[[Panegyrici Latini]]'' 8(5)12.2</ref>{{sfnm|1a1=Barnes|1y=1981|1pp=7, 288|2a1=Potter|2y=2005|2pp= 284–285, 650|3a1=Southern|3y=2001|3p=143|4a1=Williams|4y=1985|4p=55}} but this might have been an attempt to conceal an embarrassing military defeat.{{sfnm|1a1=Southern|1y=2001|1p=143|2a1=Williams|2y=1985|2p=55}} Diocletian broke off his tour of the Eastern provinces soon thereafter. He returned with haste to the West, reaching Emesa by 10 May 290,{{sfn|Cod. Justinianus|loc=9.41.9}}{{sfnm|1a1=Barnes|1y=1982|1p=51|2a1=Potter|2y=2005|2pp=285, 650}} and Sirmium on the Danube by 1 July 290.{{sfn|Cod. Justinianus|loc=6.30.6}}{{sfnm|1a1=Barnes|1y=1982|1p=52|2a1=Potter|2y=2005|2pp=285, 650}}

Diocletian met Maximian in Milan either in late December 290 or January 291.{{sfnm|1a1=Barnes|1y=1981|1p=8|2a1=Barnes|2y=1982|2p=52|3a1=Potter|3y=2005|3p=285}} The meeting was undertaken with a sense of solemn pageantry. The emperors spent most of their time in public appearances. It has been surmised that the ceremonies were arranged to demonstrate Diocletian's continuing support for his faltering colleague.{{sfn|Potter|2005|p=285}} A deputation from the Roman Senate met with the emperors, renewing its infrequent contact with the Imperial office.<ref>''[[Panegyrici Latini]]'' 11(3)2.4, 8.1, 11.3–4, 12.2.</ref>{{sfnm|1a1=Barnes|1y=1981|1pp=8, 288|2a1=Potter|2y=2005|2pp=285, 650|3a1=Williams|3y=1985|3p=56}} The choice of Milan over Rome further snubbed the capital's pride. But then it was already a long-established practice that Rome itself was only a ceremonial capital, as the actual seat of the Imperial administration was determined by the needs of defense. Long before Diocletian, [[Gallienus]] (r. 253–68) had chosen Milan for his headquarters.{{sfn|Elsner|1998|p=73}} If the panegyric detailing the ceremony implied that the true center of the empire was not Rome, but where the emperor sat ("...the capital of the empire appeared to be there, where the two emperors met"),{{sfn|Williams|1985|p=57; quoting the ''[[Panegyrici Latini]]'' 11(3)12}} it simply echoed what had already been stated by the historian [[Herodian]] in the early third century: "Rome is where the emperor is".{{sfn|Elsner|1998|p=73}} During the meeting, decisions on matters of politics and war were probably made in secret.{{sfnm|1a1=Barnes|1y=1981|1p=8|2a1=Potter|2y=2005|2pp=285, 288}} The ''Augusti'' would not meet again until 303.{{sfn|Potter|2005|p=285}}