Constantius I
54th Emperor of the Roman Empire
Reign	293–305 (as Caesar with Maximian); 305–306 (as Augustus in the west, with Galerius as Augustus in the east)
Full name	Marcus Flavius Valerius Constantius Herculius Augustus[1]
Born	31 March c. 250
Birthplace	Dardania
Died	25 July 306(306-07-25) (aged 56)
Place of death	Eboracum, Britannia
Predecessor	Maximian (with Diocletian in the East)
Successor	Flavius Valerius Severus (with Galerius in the East)
Wives	Helena (?–293) Theodora (293–306)
Offspring	Constantine the Great Flavius Dalmatius Julius Constantius Hannibalianus Flavia Julia Constantia Eutropia Anastasia
Dynasty	Constantinian
Father	Eutropius
Mother	Claudia

Constantius I (Latin: Marcus Flavius Valerius Constantius Herculius Augustus;^[2][3] c. 31 March 250 – 25 July 306), commonly known as Constantius Chlorus,^[4] was Roman Emperor from 293 to 306. He was the father of Constantine the Great and founder of the Constantinian dynasty. As Caesar he defeated the usurper Allectus in Britain and campaigned extensively along the Rhine frontier, defeating the Alamanni and Franks. Upon becoming Augustus in 305, Constantius launched a successful punitive campaign against the Picts beyond the Antonine Wall.^[5] However, Constantius died suddenly in Eburacum (York) the following year. His death sparked the collapse of the tetrarchic system of government inaugurated by the Emperor Diocletian.

Life[link]

Early career[link]

Born in Dardania,^[6] the Historia Augusta claimed Constantius was the son of Eutropius, a noble from northern Dardania, in the province of Moesia Superior, and Claudia, a niece of the emperors Claudius II and Quintillus.^[7] Modern historians suspect this maternal connection to be a genealogical fabrication created by his son Constantine I,^[8] and that his family were of humble origins.^[2] His father, however, might have been the brother of Eutropia, wife of Maximian.

Constantius was a member of the Protectores Augusti Nostri under the emperor Aurelian and fought in the east against the secessionist Palmyrene Empire.^[9] While the claim that he had been made a dux under the emperor Probus is probably a fabrication,^[10][11] he certainly attained the rank of tribunus within the army, and during the reign of Carus he was raised to the position of Praeses, or governor, of the province of Dalmatia.^[12] It has been conjectured that he switched allegiances to support the claims of the future emperor Diocletian just before Diocletian defeated Carinus, the son of Carus, at the Battle of the Margus in July 285.^[13]

In 286, Diocletian elevated a military colleague, Maximian, to the throne as co-emperor of the western provinces,^[14] while Diocletian took over the eastern provinces, beginning the process that would eventually see the division of the Roman Empire into two halves, a Western and an Eastern portion. By 288, his period as governor now over, Constantius had been made Praetorian Prefect in the west under Maximian.^[15] Throughout 287 and into 288, Constantius, under the command of Maximian, was involved in a war against the Alamanni, carrying out attacks on the territory of the barbarian tribes across the Rhine and Danube rivers.^[14] To strengthen the ties between the emperor and his powerful military servant, in 289 Constantius divorced his wife (or concubine) Helena, and married the emperor Maximian’s daughter, Theodora.^[16]

Elevation as Caesar[link]

On the reverse of this argenteus struck in Antioch under Constantius Chlorus, the tetrarchs are sacrificing to celebrate a victory against the Sarmatians.

By 293, Diocletian, conscious of the ambitions of his co-emperor for his new son-in-law, allowed Maximian to promote Constantius in a new power sharing arrangement known as the Tetrarchy.^[17] Diocletian divided the administration of the Roman Empire into two halves, a Western and an Eastern portion. Each would be ruled by an Augustus, supported by a Caesar. Both Caesars had the right of succession once the ruling Augustus died.

At Milan on March 1, 293, Constantius was formally appointed as Maximian’s Caesar.^[18] He adopted the names Flavius Valerius^[1] and was given command of Gaul, Britannia and possibly Hispania. Diocletian, the eastern Augustus, in order to keep the balance of power in the imperium^[17] elevated Galerius as his Caesar, possibly on May 21, 293 at Philippopolis.^[9] Constantius was the more senior of the two Caesars, and on official documents he always took precedence, being mentioned before Galerius.^[1] Constantius’ capital was to be located at Augusta Treverorum.

Constantius’ first task on becoming Caesar was to deal with the Roman usurper Carausius who had declared himself emperor in Britannia and northern Gaul in 286.^[9] In late 293, Constantius defeated the forces of Carausius in Gaul, capturing Bononia.^[19] This precipitated the assassination of Carausius by his rationalis Allectus, who assumed command of the British provinces until his death in 296.

Constantius spent the next two years neutralising the threat of the Franks who were the allies of Allectus,^[20] as northern Gaul remained under the control of the British usurper until at least 295.^[21] He also battled against the Alamanni, achieving some victories at the mouth of the Rhine in 295.^[22] Administrative concerns meant he made at least one trip to Italy during this time as well.^[20] Only when he felt ready (and only when Maximian finally came to relieve him at the Rhine frontier^[23]) did he assemble two invasion fleets with the intent of crossing the English Channel. The first was entrusted to Asclepiodotus, Constantius’ long serving Praetorian Prefect, who sailed from the mouth of the Seine, while the other, under the command of Constantius himself, was launched from his base at Bononia.^[24] The fleet under Asclepiodotus landed near the Isle of Wight, and his army encountered the forces of Allectus, resulting in the defeat and death of the usurper.^[25] Constantius in the meantime occupied London,^[26] saving the city from an attack by Frankish mercenaries who were now roaming the province without a paymaster. Constantius massacred all of them.^[23]

Constantius remained in Britannia for a few months, replaced most of Allectus’ officers, and the British provinces were probably at this time subdivided along the lines of Diocletian’s other administrative reforms of the Empire.^[27] The result was the division of Upper Britannia into Maxima Caesariensis and Britannia Prima, while Flavia Caesariensis and Britannia Secunda were carved out of Lower Britannia. He also restored Hadrian’s Wall and its forts.^[28]

Later in 298, Constantius fought in the Battle of Lingones (Langres) against the Alamanni. He was shut up in the city, but was relieved by his army after six hours, and defeated the enemy.^[29] He defeated them again at Vindonissa (Windisch, Switzerland),^[30] thereby strengthening the defenses of the Rhine frontier. In 300, he fought against the Franks on the Rhine frontier,^[31] and as part of his overall strategy to buttress the frontier, Constantius settled the Franks in the deserted parts of Gaul to repopulate the devastated areas.^[32] Nevertheless, over the next three years the Rhine frontier continued to occupy Constantius’s attention.^[31]

In 303, Constantius was confronted with the imperial edicts dealing with the persecution of Christians. Instituted by Diocletian, it was avidly pursued by Galerius who noticed that Constantius was well disposed towards the Christians, and saw it as a method of advancing his career prospects with the aging Diocletian.^[33] Of the four Tetrarchs, Constantius made the least effort to implement the decrees of the edicts in the western provinces that were under his direct authority,^[34] limiting himself to knocking down a handful of churches.^[35]

Accession as Augustus and death[link]

Medal of Constantius I capturing Londinium (inscribed as LON) after defeating Allectus. Beaurains hoard.

Between 303 and 305, Galerius began maneuvering to ensure that he would be in a position to take power from Constantius after the passing of Diocletian.^[36] In 304, Maximian met up with Galerius, probably to discuss the succession issue and Constantius either was not invited or could not make it due to the situation on the Rhine.^[31] Although prior to 303 there appeared to be tacit agreement between the Tetrarchs that Constantius’s son, Constantine and Maximian’s son Maxentius were to be promoted to the rank of Caesar once Diocletian and Maximian had resigned the purple,^[37] by the end of 304 Galerius had convinced Diocletian (who in turn convinced Maximian) to appoint Galerius’s nominees Severus and Maximinus Daia as Caesars.^[31]

Diocletian and Maximian stepped down as co-emperors on May 1, 305, possibly due to Diocletian's poor health.^[35] Before the assembled armies at Milan, Maximian removed his purple cloak and handed it to Severus, the new Caesar, and proclaimed Constantius as Augustus. The same scene played out at Nicomedia under the authority of Diocletian.^[38] Constantius, notionally the senior emperor, ruled the western provinces, while Galerius took the eastern provinces. Constantine, disappointed in his hopes to become a Caesar, fled the court of Galerius after Constantius had asked Galerius to release his son as Constantius was ill.^[39] Constantine joined his father's court at the coast of Gaul, just as he was preparing to campaign in Britain.^[40]

In 305 Constantius crossed over into Britain, travelled to the far north of the island and launched a military expedition against the Picts, claiming a victory against them and the title Britannicus Maximus II by 7 January 306.^[41] After retiring to Eboracum (York) for the winter, Constantius had planned to continue the campaign, but on 25 July 306, Constantius died. As he was dying, Constantius recommended his son to the army as his successor;^[42] consequently Constantine was declared emperor by the legions at York.^[43]

Family[link]

Constantius was either married to, or was in concubinage with, Helena, who was probably from Nicomedia in Asia Minor.^[44] They had one son, Constantine.

In 289 political developments forced him to divorce Helena. He married Theodora, Maximian's daughter. They had six children^[10]:

• Flavius Dalmatius
• Julius Constantius
• Hannibalianus
• Flavia Julia Constantia
• Anastasia
• Eutropia

Legend[link]

Christian legends[link]

As the father of Constantine, a number of Christian legends have grown up around Constantius. Eusebius's Life of Constantine claims that Constantius was himself a Christian, although he pretended to be a pagan, and while Caesar under Diocletian, took no part in the Emperor's persecutions.^[45] His first wife, Helena, found the True Cross.

British legends[link]

Constantius's activities in Britain were remembered in medieval British legend. According to Geoffrey of Monmouth's History of the Kings of Britain (1136), Constantius was sent to Britain by the Senate after Asclepiodotus, here a British king, was overthrown by Coel of Colchester. Coel submitted to Constantius and agreed to pay tribute to Rome, but died only eight days later. Constantius married Coel's daughter Helena and became king of Britain. He and Helena had a son, Constantine, who succeeded to the throne of Britain when his father died at York eleven years later.^[46] The identification of Helena as British had previously been made by Henry of Huntingdon,^[47] but has no historical validity: Constantius had divorced Helena before he went to Britain.

Sources[link]

Primary sources[link]

• Aurelius Victor, Epitome de Caesaribus
• Joannes Zonaras, Compendium of History 1050581 extract: Diocletian to the Death of Galerius: 284-311
• Zosimus, Historia Nova

Secondary sources[link]

• Southern, Pat. The Roman Empire from Severus to Constantine, Routledge, 2001
• Potter, David Stone, The Roman Empire at Bay, AD 180-395, Routledge, 2004
• Birley, Anthony (2005), The Roman Government in Britain, Oxford University Press, ISBN 978-0-19-925237-4 
• Jones, A.H.M., Martindale, J.R. The Prosopography of the Later Roman Empire, Vol. I: AD260-395, Cambridge University Press, 1971
• Canduci, Alexander (2010), Triumph & Tragedy: The Rise and Fall of Rome's Immortal Emperors, Pier 9, ISBN 978-1-74196-598-8 
• http://www.roman-emperors.org/chlorus.htm DiMaio, Robert, "Constantius I Chlorus (305–306 A.D.)", De Imperatoribus Romanis] (1996)

References[link]

External links[link]

Media related to Constantius Chlorus at Wikimedia Commons

• Constantius Chlorus on History of York website

Constantius II
61st Emperor of the Roman Empire
Bust of Constantius II
Reign	324 (13 November) – 337 (22 May): Caesar under his father, Constantine I 337 – 340: co-Augustus (ruled Asian provinces & Egypt) with Constantine II and Constans 340 – 350: co-Augustus (ruled Asian provinces & Egypt) with Constans 350 – 361 (3 November): Sole Augustus of the Roman Empire
Full name	Flavius Julius Constantius (from birth to accession); Flavius Julius Constantius Caesar (as Caesar); Flavius Julius Constantius Augustus (as Augustus)
Born	(317-08-07)7 August 317
Birthplace	Sirmium, Pannonia Inferior (Sremska Mitrovica, Serbia)
Died	3 November 361(361-11-03) (aged 44)
Place of death	Mopsuestia, Cilicia
Predecessor	Constantine I
Successor	Julian
Wives	1) Daughter of Julius Constantius 2) Eusebia 3) Faustina
Offspring	Flavia Maxima Constantia, born posthumously, later married Gratian
Dynasty	Constantinian
Father	Constantine I
Mother	Fausta

Constantius II (Latin: Flavius Julius Constantius Augustus;^[1][2] 7 August 317 – 3 November 361), was Roman Emperor from 337 to 361. The second son of Constantine I and Fausta, he ascended to the throne with his brothers Constantine II and Constans upon their father's death.

In 340, Constantius' brothers clashed over the western provinces of the empire. The resulting conflict left Constantine II dead and Constans as ruler of the west until he was overthrown and assassinated in 350 by the usurper Magnentius. Unwilling to accept Magnentius as co-ruler, Constantius marched against him. Magnentius was defeated at the battles of Mursa Major and Mons Seleucus, committing suicide after the latter. This left Constantius as sole ruler of the empire.

His subsequent military campaigns against Germanic tribes were successful: he defeated the Alamanni in 354, and campaigned across the Danube against the Quadi and Sarmatians in 357. Contrastingly, in the east, the two decade old war against the Sassanids continued with mixed results.

As a consequence of the difficulty of managing the entire empire alone, Constantius elevated two of his cousins to the subordinate rank of Caesar. Constantius Gallus, the eldest surviving son of Constantius' half-uncle, Julius Constantius, was promoted in 351, but executed three years later for his supposedly violent and corrupt nature. Constantius then promoted Gallus' younger half-brother, Julian, who was Constantius' last surviving cousin and the man who would ultimately succeed him, in 355.

However, the actions of Julian in claiming the rank of Augustus in 360 led to war between the two. Ultimately, no battle ever took place as Constantius became ill and died late in 361, though not before naming his opponent as his successor.

Life[link]

Division of the Roman Empire among the Caesars appointed by Constantine I: from left to right, the territories of Constantine II, Constans I, Dalmatius and Constantius II. After the death of Constantine I (May 337), this was the formal division of the Empire, until Dalmatius was killed and his territory divided between Constans and Constantius.

Constantius was born in 317 at Sirmium, Pannonia. He was the third son of Constantine the Great, and second by his second wife Fausta, the daughter of Maximian. Constantius was made Caesar by his father on 13 November 324.^[3] In 336, religious unrest in Armenia and tense relations between Constantine and king Shapur II caused war to break out between Rome and Sassanid Persia.^[4] Though he made initial preparations for the war, Constantine fell ill and sent Constantius east to take command of the eastern frontier.^[4][5] Before Constantius arrived, the Persian general Narses, who was possibly the king's brother, overran Mesopotamia and captured Amida. Constantius promptly attacked Narses, and after suffering minor setbacks defeated and killed Narses at the Battle of Narasara.^[6] Constantius captured Amida and initiated a major refortification the city, enhancing the city's circuit walls and constructing large towers. He also built a new stronghold in the hinterland nearby, naming it Antinopolis.^[7]

Augustus in the East[link]

Missorium of Kerch depicting Constantius II on horseback with a spear. He is preceded by victory and accompanied by a guardsman.

Constantius II coin, celebrating the 15th year of his reign.

In early 337, Constantius hurried to Constantinople after receiving news that his father was near death.^[8] After Constantine died, Constantius buried his father with lavish ceremony in the Church of the Holy Apostles.^[9] Soon after his father's death Constantius is supposed to have ordered a massacre of his relatives descended from the second marriage of his paternal grandfather Constantius Chlorus, though the details are unclear.^[10][11] Eutropius, writing between 350 and 370, writes that Constantius merely sanctioned “the act, rather than commanding it”.^[12] The massacre killed two of Constantius' uncles and six of his cousins,^[13] including Hannibalianus and Dalmatius, rulers of the Pontus and Moesia respectively. The massacre left Constantius, his older brother Constantine II, his younger brother Constans, and three cousins Gallus, Julian and Nepotianus as the only surviving male relatives of Constantine the Great. Soon after, Constantius met his brothers in Pannonia at Sirmium to formalize the partition of the empire.^[14] Constantius received the eastern provinces, including Constantinople, Thrace, Asia Minor, Syria, Egypt, and Cyrenaica. Constantine received Britannia, Gaul, Hispania, and Mauretania, while Constans, though initially under the supervision of Constantine II, received Italy, Africa, Illyricum, Pannonia, Macedonia, and Achaea.^[15]

After, Constantius hurried east to Antioch to resume the war with Persia.^[16] While Constantius was away from the eastern frontier in early 337, Shapur assembled a large army, including war elephants, and launched an attack on Roman territory, laying waste to Mesopotamia^[17] and putting Nisibis under siege.^[18] Despite initial success, Shapur lifted his siege after his army missed an opportunity to exploit a collapsed wall.^[19] When Constantius learned of Shapur's withdrawal from Roman territory, he prepared his army for a counter-attack, drilling them and upgrading the equipment of his cataphracts. He spent most of his time defending the eastern border against invasions by the aggressive Sassanid Empire under king Shapur II. These conflicts were mainly limited to Sassanid sieges of the major fortresses of Roman Mesopotamia, including Nisibis (Nusaybin), Singara, and Amida (Diyarbakir). Although Shapur seems to have been victorious in most of the confrontations, the Sassanids were able to achieve little.^[20][21] However, the Romans won a decisive victory at the Battle of Narasara, killing Shapur's brother, Narses.^[20][22] Ultimately, Constantius was able to push back the invasion, Shapur failing to make any significant gains.^[21] Meanwhile, his brother Constantine desired to retain control of Constans' realm – leading Constantius' two brothers into open conflict. Constantine was killed in 340 near Aquileia during an ambush.^[12] As a result, Constans took control of his deceased brother’s realms and became sole ruler of the Western two-thirds of the empire. This division lasted until 350, when Constans was assassinated by forces loyal to the usurper Magnentius.^[12][23]