The Conference of Carnuntum was a gathering of ancient Roman rulers on 11 November 308, intended to stabilize the power-sharing arrangement known as the

Tetrarchy The Tetrarchy was the system instituted by Roman emperor Diocletian in 293 AD to govern the ancient Roman Empire by dividing it between two emperors, the ''augusti'', and their junior colleagues and designated successors, the ''caesares''. I ...

. It was convened by the Eastern ''augustus'' (

emperor The word ''emperor'' (from , via ) can mean the male ruler of an empire. ''Empress'', the female equivalent, may indicate an emperor's wife (empress consort), mother/grandmother (empress dowager/grand empress dowager), or a woman who rules ...

)

Galerius Galerius Valerius Maximianus (; Greek: Γαλέριος; 258 – May 311) was Roman emperor from 305 to 311. He participated in the system of government later known as the Tetrarchy, first acting as '' caesar'' under Emperor Diocletian. In th ...

(r. 305–311) in the city of

Carnuntum Carnuntum ( according to Ptolemy) was a Roman legionary fortress () and headquarters of the Roman navy, Pannonian fleet from 50 AD. After the 1st century, it was capital of the Pannonia Superior province. It also became a large city of app ...

(present-day

Petronell-Carnuntum Petronell-Carnuntum is a community of Bruck an der Leitha in Austria. It is known for its proximity to the former Roman fort of Carnuntum. History The village derives the second half of its name, Carnuntum, from the ancient Roman legionary fo ...

Austria Austria, formally the Republic of Austria, is a landlocked country in Central Europe, lying in the Eastern Alps. It is a federation of nine Federal states of Austria, states, of which the capital Vienna is the List of largest cities in Aust ...

), which at the time was located in the

Roman province The Roman provinces (, pl. ) were the administrative regions of Ancient Rome outside Roman Italy that were controlled by the Romans under the Roman Republic and later the Roman Empire. Each province was ruled by a Roman appointed as Roman g ...

Pannonia Prima Pannonia Prima was an ancient Roman province. It was formed in the year 296, during the reign of Emperor Diocletian. Previously, it was a part of the province of Pannonia Superior, which, along with Pannonia Inferior, was gradually divided into ...

. A dispute over the title of ''augustus'' in the West had been ongoing since the previous year, when consecutive invasions by

Severus II Flavius Valerius Severus (died September 307), enumerated as Severus II, was a Roman emperor from 306 to 307, and a member of the Tetrarchy. He shared control of the western half of the empire with Constantine I, but spent most of his short re ...

(r. 306–307) and Galerius had failed to recover Italy from the usurpers

Maxentius Marcus Aurelius Valerius Maxentius ( 283 – 28 October 312) was a Roman emperor from 306 until his death in 312. Despite ruling in Italy and North Africa, and having the recognition of the Senate in Rome, he was not recognized as a legitimate ...

(r. 306–312) and

Maximian Maximian (; ), nicknamed Herculius, was Roman emperor from 286 to 305. He was ''Caesar (title), Caesar'' from 285 to 286, then ''Augustus (title), Augustus'' from 286 to 305. He shared the latter title with his co-emperor and superior, Diocleti ...

(r. 286–305, 306–308). Present at the conference were the retired

Diocletian Diocletian ( ; ; ; 242/245 – 311/312), nicknamed Jovius, was Roman emperor from 284 until his abdication in 305. He was born Diocles to a family of low status in the Roman province of Dalmatia (Roman province), Dalmatia. As with other Illyri ...

(r. 284–305), and his former colleague, Maximian. According to deliberations at the meeting, Maximian was to retire permanently from his imperial position;

Licinius Valerius Licinianus Licinius (; Ancient Greek, Greek: Λικίνιος; c. 265 – 325) was Roman emperor from 308 to 324. For most of his reign, he was the colleague and rival of Constantine I, with whom he co-authored the Edict of Milan that ...

(r. 308–324), a former general of Galerius, was raised as the western Augustus and was to deal with Maxentius, who had been treated as an

usurper A usurper is an illegitimate or controversial claimant to power, often but not always in a monarchy. In other words, one who takes the power of a country, city, or established region for oneself, without any formal or legal right to claim it a ...

; and

Constantine Constantine most often refers to: * Constantine the Great, Roman emperor from 306 to 337, also known as Constantine I * Constantine, Algeria, a city in Algeria Constantine may also refer to: People * Constantine (name), a masculine g ...

(r. 306–337) was relegated, for the second time, to western ''caesar''. These decisions, however, did not please most of them: Constantine questioned his demotion and persisted in using the style of ''augustus''; Maximinus (r. 305–313) demanded promotion from Galerius; Maximian would not be satisfied with his demotion and would attempt one last conspiracy, in 310, at the court of Constantine in

Arles Arles ( , , ; ; Classical ) is a coastal city and Communes of France, commune in the South of France, a Subprefectures in France, subprefecture in the Bouches-du-Rhône Departments of France, department of the Provence-Alpes-Côte d'Azur Reg ...

, while Licinius would do nothing in the following years to stop Maxentius.

Background

Since March 293, the

Roman Empire The Roman Empire ruled the Mediterranean and much of Europe, Western Asia and North Africa. The Roman people, Romans conquered most of this during the Roman Republic, Republic, and it was ruled by emperors following Octavian's assumption of ...

had been governed by four tetrarchs, a set of two ''augusti'' (emperors) and two ''caesares'' (heirs) for each of the western and eastern portions. On 1 May 305, the ''augusti''

(r. 284–305) and

(r. 285–305) voluntarily abdicated and their ''caesares''

Constantius Constantius may refer to: __NOTOC__ Roman people * Constantius I "Chlorus" (–306), Western Roman emperor from 305 to 306 * Julius Constantius (died 337), consul in 335, son of Constantius I * Constantius Gallus (325–354), ''caesar'' from 351 to ...

(r. 293–306) and

(r. 293–311) were elevated to the western and eastern augustal position respectively, while

(r. 305–307) and

Maximinus Daza Galerius Valerius Maximinus, born as Daza (; 20 November 270 – July 313), was Roman emperor from 310 to 313. He became embroiled in the civil wars of the Tetrarchy between rival claimants for control of the empire, in which he was defeated ...

(r. 305–313) would become the western and eastern ''caesares'', respectively. Constantius died at

Eboracum Eboracum () was a castra, fort and later a coloniae, city in the Roman province of Roman Britain, Britannia. In its prime it was the largest town in northern Britain and a provincial capital. The site remained occupied after the decline of the ...

(present-day

York York is a cathedral city in North Yorkshire, England, with Roman Britain, Roman origins, sited at the confluence of the rivers River Ouse, Yorkshire, Ouse and River Foss, Foss. It has many historic buildings and other structures, such as a Yor ...

England England is a Countries of the United Kingdom, country that is part of the United Kingdom. It is located on the island of Great Britain, of which it covers about 62%, and List of islands of England, more than 100 smaller adjacent islands. It ...

) on 25 July 306, and his soldiers acclaimed his son

(r. 306–337) as his successor. However, as per the arrangement of the prevailing

, Galerius elevated

(r. 305–307) as the new ''augustus'' of the West in opposition to Constantine. After some diplomatic discussions, Galerius relegated Constantine to the position of ''caesar'', which he accepted, thus allowing Severus to assume his position. Severus II Aureus Joanneum

(r. 306–312), son of

, was jealous of Constantine's elevation, and during a riot over capitation tax in Rome, a cohort of

praetorian guards The Praetorian Guard (Latin: ''cohortes praetoriae'') was the imperial guard of the Imperial Roman army that served various roles for the Roman emperor including being a bodyguard unit, counterintelligence, crowd control and gathering milita ...

acclaimed him emperor on 28 October 306, though at first he styled himself ''princeps invictus'' ("undefeated prince"), in the hope of obtaining recognition of his reign by the senior emperor Galerius. Then, uncomfortable with sole leadership, Maxentius sent a set of imperial robes to Maximian and saluted him as "augustus for the second time", offering him theoretical equal rule but less actual power and a lower rank. By 307, both had suffered invasions. The first by Severus II, who surrendered to Maximian, after which Maxentius publicly assumed the style of ''augustus'', and then by Galerius himself, who ultimately decided to withdraw. Before or during Galerius' invasion, Severus was executed or was forced to commit suicide. Soon afterwards, Maximian made his way to Gaul to negotiate with Constantine. A deal was struck in which Constantine would marry Maximian's younger daughter

Fausta Flavia Maxima Fausta ''Augusta'' (died 326 AD) was a Roman empress. She was the daughter of Maximian and wife of Constantine the Great, who had her executed and excluded from all official accounts for unknown reasons. Historians Zosimus and ...

and be elevated to augustan rank in Maxentius' secessionist regime. In return, Constantine would reaffirm the old family alliance between Maximian and Constantius, and support Maxentius' cause in Italy but would remain neutral in the war with Galerius. The deal was sealed with a double ceremony in

Augusta Treverorum Augusta Treverorum (Latin for "City of Augustus in the Land of the Treveri") was a Ancient Rome, Roman city on the Moselle River, from which modern Trier emerged. The date of the city's founding is placed between the construction of the first Rom ...

(present day

Trier Trier ( , ; ), formerly and traditionally known in English as Trèves ( , ) and Triers (see also Names of Trier in different languages, names in other languages), is a city on the banks of the Moselle (river), Moselle in Germany. It lies in a v ...

Germany Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total popu ...

) in late 307, at which Constantine married Fausta and was declared ''augustus'' by Maximian. In 308, likely in April, Maximian attempted to depose his son in a failed plot, forcing him to flee Italy in disgrace, and eventually to Constantine's court in

Gaul Gaul () was a region of Western Europe first clearly described by the Roman people, Romans, encompassing present-day France, Belgium, Luxembourg, and parts of Switzerland, the Netherlands, Germany, and Northern Italy. It covered an area of . Ac ...

. Aware of the situation in the west, Galerius decided to organize a conference, and Maximian pinned his hopes for re-ascension on it.

Conference

On 11 November 308, Galerius convened the Conference of

(now

) to try to stabilize the situation in the western provinces. Present at the conference were the retired emperor Diocletian, who briefly returned to public life, Galerius, and Maximian. At the conference, Maximian was forced to abdicate again, and Constantine was re-relegated to his former position as ''caesar''. In addition,

, one of Galerius' military companions who was attending the conference, was acclaimed as the new ''augustus'' in the West, and was given the regions of

Thrace Thrace (, ; ; ; ) is a geographical and historical region in Southeast Europe roughly corresponding to the province of Thrace in the Roman Empire. Bounded by the Balkan Mountains to the north, the Aegean Sea to the south, and the Black Se ...

Pannonia Pannonia (, ) was a Roman province, province of the Roman Empire bounded on the north and east by the Danube, on the west by Noricum and upper Roman Italy, Italy, and on the southward by Dalmatia (Roman province), Dalmatia and upper Moesia. It ...

, and

Illyria In classical and late antiquity, Illyria (; , ''Illyría'' or , ''Illyrís''; , ''Illyricum'') was a region in the western part of the Balkan Peninsula inhabited by numerous tribes of people collectively known as the Illyrians. The Ancient Gree ...

, as well as the mission of neutralizing Maxentius in Italy. Finally, the ''augusti'' present rebuilt the

Mithraeum A Mithraeum , sometimes spelled Mithreum and Mithraion (), is a Roman temple, temple erected in classical antiquity by the Mithraism, worshippers of Mithras. Most Mithraea can be dated between 100 BC and 300 AD, mostly in the Roman ...

of Carnuntum and dedicated it to the absent ''caesares'' (Constantine and

) and themselves: For the scholar A. L. Frothingham, considering that by the fourth century the cult of

Mithras Mithraism, also known as the Mithraic mysteries or the Cult of Mithras, was a Roman Empire, Roman mystery religion focused on the god Mithras. Although inspired by Iranian peoples, Iranian worship of the Zoroastrian divinity (''yazata'') Mit ...

and the

Sol Invictus Sol Invictus (, "Invincible Sun" or "Unconquered Sun") was the official Solar deity, sun god of the late Roman Empire and a later version of the god Sol (Roman mythology), Sol. The emperor Aurelian revived his cult in 274 AD and promoted Sol Inv ...

was on the rise, it is not surprising that a dedication was made to these gods in the name of the emperors. According to him, this could be interpreted as a symbolic handing over of the state to these gods, who from that moment on would have the mission to guard it and prevent it from returning to the

Crisis of the Third Century The Crisis of the Third Century, also known as the Military Anarchy or the Imperial Crisis, was a period in History of Rome, Roman history during which the Roman Empire nearly collapsed under the combined pressure of repeated Barbarian invasions ...

. File:Diocletian medallion (obverse).jpg, Medallion of

, 303 File:Aureus of Maximian (obverse).jpg, Aureus of

, c. 294 File:Galeriuscng90030228obverse.jpg,

Argenteus The ''argenteus'' ( ''argentei'', 'of silver') was a silver coin produced by the Roman Empire from the time of Diocletian's coinage reform in AD 294 to ca. AD 310. It was of similar weight and fineness to the denarius of the time of Nero. The coi ...

, c. 306 File:Rare aureus of Licinius I (obverse).jpg,

Solidus Solidus (Latin for "solid") may refer to: * Solidus (coin) The ''solidus'' (Latin 'solid'; : ''solidi'') or ''nomisma'' () was a highly pure gold coin issued in the Later Roman Empire and Byzantine Empire. It was introduced in the early ...

, c. 312 File:Maximinus Caesar (obverse).jpg, Aureus of

Maximinus II Galerius Valerius Maximinus, born as Daza (; 20 November 270 – July 313), was Roman emperor from 310 to 313. He became embroiled in the civil wars of the Tetrarchy between rival claimants for control of the empire, in which he was defeated ...

, 313 File:Aureus of Constantine I as Caesar.jpg, Solidus of

Constantine I Constantine I (27 February 27222 May 337), also known as Constantine the Great, was a Roman emperor from AD 306 to 337 and the first Roman emperor to convert to Christianity. He played a Constantine the Great and Christianity, pivotal ro ...

, 307

Consequences

The new system would not last long: Constantine refused to accept his relegation and continued to portray himself as ''augustus'' on his coinage, even though the other members of the Tetrarchy continued to refer to him as ''caesares''. Meanwhile, Licinius did nothing to remove the usurper Maxentius from power and preferred to deal with internal problems and barbarian incursions in the provinces vested in him. Furthermore, Maximinus Daza, frustrated at being disregarded as a possible occupant of the position granted to Licinius, demanded a promotion from Galerius. Galerius offered to call both Maximinus and Constantine ''filii augustorum'' ("sons of the ''augustus''", sing. ''filius augustī''), a title they both refused. Between late 309 to the spring of 310, however, Galerius relented and called them each ''augustus'', which resulted in a situation of five full ''augusti'' ruling the empire. In early 310, taking advantage of Constantine's absence on the Rhine frontier fighting against

Frankish Frankish may refer to: * Franks, a Germanic tribe and their culture ** Frankish language or its modern descendants, Franconian languages, a group of Low Germanic languages also commonly referred to as "Frankish" varieties * Francia, a post-Roman ...

invaders, Maximian revolted at

Arelate Arles ( , , ; ; Classical ) is a coastal city and commune in the South of France, a subprefecture in the Bouches-du-Rhône department of the Provence-Alpes-Côte d'Azur region, in the former province of Provence. A large part of the ...

(present-day

France France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...

) and tried to take his position. He would gain little support for the revolt and soon Constantine would become aware of what had occurred. He immediately headed south and easily quelled the revolt, capturing Maximian and encouraging him to commit suicide. The following year, Maxentius, calling for revenge for his father's death, declared war on Constantine, who responded with an invasion of northern Italy in 312. In the same year, Galerius died and the Eastern Roman Empire is divided between Maximinus and Licinius, who after some disagreements, decided to sign a peace in 312 on the Bosphorus. It would be short-lived, with them declaring war on each other by 313.

References

{{Reflist Roman Empire Ancient history Conferences Emperors Tetrarchy Diocletian Galerius Constantine the Great Constantinian dynasty

Background

Conference

Consequences

See also

References