Britannic coinage and the Tetrarchy

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Last updated: 20 December 2019

Significant Historical Events and London Mint Coinage

Diocletian's Tetrarchic system of Governance

Diocletian (Caius Aurelius Verus Diocletianus) was proclaimed Augustus in AD 284. The following year he appointed Marcus Aurelius Valerius Maximianus (Maximian Herculius), a close military comrade, as his Caesar elevating him to co-Augustus a year later thereby creating a Dyarchy.

In 293 Diocletian finalized the Institution of a Tetrarchy -- government of the Empire by four interacting rulers -- two Augusti assisted by two subordinate Caesars, which each Augustus would personally select. The two Caesars, chosen because of their proven leadership abilities, assisted the Augusti with civil administration and command of the armies. Caius Galerius Valerius Maximianus (Galerius Maximian) was chosen by Diocletian to be his Caesar of the East and Flavius Valerius Constantius (Constantius) was chosen by Maximian Herculius to be his Caesar of the West. The Empire was divided into four geographical areas of governance: Diocletian and Galerius Maximian maintained their eastern headquarters at Nicomedia and Thessalonica respectively, while Maximian Herculius and Constantius maintained their western headquarters at Milan and Trier respectively.

Problem with Roman occupied Britain and the emergence of Carausius

The political and military turmoil of the third century spawned numerous external assaults on the Roman Empire. One of these was the incessant seafaring piracy in the waters surrounding the Roman occupied island outpost of Britain. In 286 Maximian Herculius, in his capacity as Dyarch Augustus of the West, designated a highly regarded military commander named Marcus Aurelius Mausaeus Carausius, of Flemish descent, to head a fleet of ships who's mission was to eliminate, or at least severely curtail, this piracy. Carausius had distinguished himself by outstanding leadership and military prowess, especially as a naval "Admiral", in the Gallic campaigns. Carausius established his operational base at the coastal city of Boulogne (Gesoriacum) in Roman occupied northern Gaul. Carausius did indeed accomplish his mission, but reports of corruption and extortion led Maximian Herculius to dispatch a fleet of ships in order to remove Carausius from command. However, Carausius proved too strong and he repulsed the attack.

Carausius - Usurper Augustus of Secessionist Britain

Carausius subsequently used his continental base to launch an invasion force to occupy and subjugate Britain. Landing in the north, Carausius secured the support of the native Picts and, advancing south, confronted and defeated the forces of the Roman Governor. Having thus conquered the Island, he proclaimed himself Augustus of a Secessionist Britain, becoming an effective and efficient Administrator using the Roman Imperial governmental framework as a model. He maintained control of Boulogne and coastal northern Gaul.

The Mints of Carausius

Carausius established two Britannic mints - a primary one at London (Londinium) and one at Colchester/Camulodunum/Clausentum - "C" Mint - plus a ContinentaL mint across the Channel in Gaul These mints produced coins of distinctive style in gold, silver and bronze (mostly antoniniani).

RIC V (2), Carausius, No. 475:


IMP C CARAVSIVS PF AVG ......................................... PA - X - AVG | S .....P

Draped, radiate, bust
London Mint.
3.9 gm.

Allectus - Successor Usurper Augustus of Secessionist Britain

In AD 293, Allectus, the chief minister of Carausius, assassinated him (or orchestrated his assassination) and proclaimed himself Augustus of Secessionist Britain. He continued to operate the British Carausian mints but added a new AE denomination: Quinarius (half antoninianus) which was a copper coin of reduced size bearing the letter Q in the exergue, which has been interpreted to mean Quinarius (half antoninianus).

RIC V (2), Allectus, No. 33:


IMP C ALLECTVS P F AVG ............................. PA - X - AVG ..... S (Pax standing left) A
M L in reverse exergue.

Cuirassed, radiate, bust
London mint
5.1 gm.
Allectus died in battle with the invading force of Constantius in southern Britain AD 296

The Britannic Invasion coinage of Constantius minted in Gaul

One of the earliest issues of the reformed Ae coinage resulted from the the first assignment given Constantius by Maximian Herculius in 294 which was to restore secessionist Britain to the Roman Empire. The first order of business for Constantius was to insure that a supply of these coins - now the commonplace legal tender of the Roman Empire - was available for use not only by his occupying force, but also by the British civilian populace. To that end Constantius established a Mint in Gaul (location usually listed as unknown, although some French sources list it as Boulogne), manned by Lugdunese mint workers, to produce this invasion coinage - unmarked (i.e. without a mint mark) issued in the names of Diocletian & Maximian Herculius as Augusti and Constantius & Galerius Maximian as Caesars, which constituted the First Tetrarchy.

RIC Volume VI, Lugdunum, No. 17a, Constantius, Caesar of the West:

[Constantius coin photo][Constantius coin photo]
FL VAL CONSTANTIVS NOB C .............................. GENIO POPV -- LI ROMANI

Earliest obverse legend
10.1 gm.
Britannia invasion coinage produced in Gaul at unknown Continental mint

Restoration of Secessionist Britain to the Empire by Constantius

In 296 Constantius launched a powerful naval invasion force against Britain in two divisions: one led by himself, which sailed from Boulogne and the other led by the Praetorian Prefect of Maximian Herculius, Asclepiodotus, which sailed from the mouth of the river Seine. The mission of Constantius was to remove Allectus from power and restore Britain to the Empire. This mission was accomplished and although Constantius was in overall command of the operation, some historical sources assert it was the force under Asclepiodotus that did most of the fighting on land and in fact it was they who defeated and killed Allectus during the decisive battle. Constantius subsequently entered the city of London to proclaim his conquest as restorer of the eternal light of the Roman Empire: Redditor Lucis Aeternae.

The London Mint re-opened by Constantius

Constantius re-opened the former Carausius/Allectus London Mint, as an official facility with one officina (workshop), which continued to operate, somewhat sporadically, until its closure in 325. It seems very likely that initially the work force consisted of British die engravers and other workers, formerly employed by the Carausius/Allectus Mints, now supervised and mixed in with Lugdunese mint workers who accompanied the Constantius invasion force.

Characteristics of the reformed AE coinage produced by the London Mint

Composition -- bronze with a silver wash.

Weight range -- Initially 11 to 9 grams which declines to ± 4 grams by 313.

Obverse depictions -- Mostly cuirassed (sometimes draped) right facing busts (but occasionally bare neck truncated) with a laureate head.

Reverse depiction -- Mostly a representation of the Genius of the Roman People standing, facing left, head surmounted by a modius, naked except for a chlamys over the left shoulder, holding a patera in the right hand and cradling a cornucopia in the left arm. Very rarely, and mostly after 1 May 305, Genius is depicted with loins draped, and wearing a towered head-dress.

This London Mint continued to produce exclusively this coinage, first under Constantius and then under Constantine, until its closure in AD 325.

Initial re-opened London Mint coinage

The coin obverses and reverses of the initial production coin series replicate those of the Constantius Invasion coinage except there is now a LON mint mark in the exergue.

SELECTED EXAMPLE COIN:

RIC Volume VI, Londinium, No.1a, Diocletian, Augustus of the East
CT (Cloke & Toone), No. 1.01.001, c. AD 296, Rarity: R

[Diocletian coin photo][Diocletian coin photo]
IMP C DIOCLETIANVS PF AVG .................... GENIO POPV -- LI ROMANI
LON
in reverse exergue

As depicted in RIC Volume VI, Plate 1.
Subsequent coinage after this series (RIC VI, Londinium, Nos. 1-5) was unmarked (i.e. no LON mint mark) until the issue of reduced size/weight folles after the death of Constantius.
9.8 gm.

Intermediate London Mint coinage (Bastien)

The coin obverses and reverses in this series replicate those of the Constantius Invasion coinage except in some instances the obverse busts are cuirassed (including some with elaborate consular features) and have London mint style small and compact inscriptional lettering. These intermediate style folles were issued immediately following the LON marked coins.

SELECTED EXAMPLE COIN

Intermediate series coin (Bastien), not in RIC, Galerius Maximian, Caesar of the East
CT (Cloke & Toone), No. 1.02.004 (2), c. AD 296, Rarity: R

[Galerius coin photo][Galerius coin photo]
C VAL MAXIMIANVS NOB C ........................... GENIO POPV -- LI ROMANI

Laureate with truncated bare neck bust.
Long wreath ribbon tie laying on neck
10.1 gm.

Subsequent London Mint coinage

The coin obverses follow an almost standard pattern - right facing laureate, cuirassed busts with short wreath ribbon ties secured behind the neck. The reverses depict what was by now the standard representation of the Genius of the Roman People standing, facing left, head surmounted by a modius, naked except for a chlamys over the left shoulder, holding a patera in the right hand and cradling a cornucopia in the left arm. Both the obverse and reverse inscriptional lettering is somewhat thick and compact with the legends reading clockwise around the periphery of the coin. The reverse legend is almost always GENIO POPVLI ROMANI. There is no mint mark in the exergue.

SELECTED EXAMPLE COINS

RIC VI, Londinium, No.6b, Maximian Herculius, Augustus of the West
CT (Cloke & Toone), No. 2.01.007 (5), c. AD 296-303, Rarity: C


IMP C MAXIMIANVS PF AVG ................. GENIO POPV -- LI ROMANI

Laureate, cuirassed, bust.
10.1 gm.


RIC VI, Londinium, No. 20, Constantius, Caesar of the West
CT (Cloke & Toone), No. 2.01.010 (1), c. AD 296-303, Rarity: C

[Galerius coin photo][Galerius coin photo]
FL VAL CONSTANTIVS NOB C ........................... GENIO POPV -- LI ROMANI

Laureate, cuirassed, bust with long ribbon tie laying on neck.
London style lettering.
9.8 gm.

Diocletian plans his Abdication - and includes a reluctant Maximian Herculius

It seems Diocletian had always envisioned that there would come a time when he (along with his co-Augustus) would have to relinquish the reins of supreme power and retire (for whatever reason). He chose the occasion of his Vicennalia -- the twentieth anniversary of his assumption of power as Augustus and coincidentally the tenth anniversary (Decinnelia) of his institution of the Tetrarchy -- to Abdicate and retire and persuaded (compelled?) Maximian Herculius to do the same in concert with him. And so, in 303 the two Augusti announced their intention to simultaneously abdicate and retire (Maximian Herculius somewhat reluctantly) in 305, their titles and authority to be assumed by the Caesars, who in turn would appoint new Caesars thus perpetuating the system. This was the only instance of an Abdication during the Tetrarchy -- it didn't survive as an institution long enough to witness another one. Although Diocletian had provided a model for perpetuation of the system attending an Abdication, he didn't provide one to follow in the event of the sudden death of one, or both, of the reigning Augusti, and that had dire consequences for the Tetrarchy when Constantius (Augustus of the West) died suddenly in 306.

Severe illness of Diocletian

In 304 Diocletian became very ill (unknown cause - possibly a stroke) that resulted in a lengthy convalescense and withdrawal from public life.

Abdication of Diocletian and Maximian Herculius

On 1 May 305, Diocletian and Maximian Herculius abdicated to become Seniore (retired) Augusti.

Abdication coinage of Diocletian & Maximian Herculius

The obverses of these commemorative coins depict laureate busts of the Augusti in Imperial mantle holding mappa in right hand and olive branch in left hand. The reverses depict a personification of Providentia, standing left, extending hand to personification of Quies, standing right, holding olive branch and leaning on scepter.

SELECTED EXAMPLE COINS:

RIC VI, Londinium, No. 77a, Diocletian, retired senior Augustus
CT (Cloke & Toone), No. 4.01.002, c. May 305 - Spring 307, Rarity: C

[Abdication coin photo][Abdication coin photo]
DN DIOCLETIANO FELICISSIMO SEN AVG
PROVIDENTIA DEORVM QVIES AVGG

9.5 gm.

RIC VI, Londinium, No. 76b, Maximian Herculius, retired senior Augustus
CT (Cloke & Toone), No. 4.01.003, c. May 305 - Spring 307, Rarity: R

[Abdication coin photo][Abdication coin photo]
DN MAXIMIANO BEATISSIMO SEN AVG
PROVIDENTIA DEORVM QVIES AVGG

9.8 gm.

The successor Tetrarchs

On 1 May 305, Constantius succeeded Maximian Herculius as Augustus of the West and Galerius Maximian succeeded Diocletian as Augustus of the East. Flavius Valerius Severus (Severus), a close friend of Galerius Maximian, was appointed Caesar of the West by Constantius and Galerius Valerius Maximinus Daia (also known as Maximinus Daza, nephew by marriage of Galerius Maximian) was appointed Caesar of the East by Galerius Maximian.

Coinage of the successor Tetrarchs

SELECTED EXAMPLE COINS:
(The Second Tetrarchy)

RIC VI, Londinium, No. 47, Constantius, Augustus of the West
CT (Cloke & Toone), No. 4.02.003, 1 May 305 - 26 July 306, Rarity: S

[Constantius coin photo][Constantius coin photo]
IMP CONSTANTIVS PIVS FEL AVG ....................... GENIO POPV -- LI ROMANI

Earliest obverse legend style.
Laureate, cuirassed, bust.
9.9 gm.

RIC VI, Londinium, No. 42, Galerius Maximian, Augustus of the East
CT (Cloke & Toone), No. 4.03.004, AD 1 May 305 - Spring 307, Rarity: S

[Galerius coin photo][Galerius coin photo]
IMP C MAXIMIANVS P F AVG ......................... GENIO POPV -- LI ROMANI

Laureate, cuirassed, bust.
Identical obverse inscription (2C) to the primary one of Maximian Herculius.
9.7 gm.

RIC VI, Londinium, No. 59a, Severus, Caesar of the West
CT (Cloke & Toone), No. 4.02.016, 1 May 305 - 26 July 306, Rarity: C

[Severus coin photo][Severus coin photo]
SEVERVS NOBILISSIMVS CAES ......................... GENIO POPV -- LI ROMANI

Earliest obverse legend style.
Draped, laurate, bust.
10.3 gm.

RIC VI, Londinium, No. 65, Maximinus (Daia), Caesar of the East:
CT (Cloke & Toone), No. 4.03.031, 1 May 305 - Spring 307, Rarity: S

[Maximinus coin photo][Maximinus coin photo]
MAXIMINVS NOBILI CAES ......................... GENIO POPV -- LI ROMANI

Draped, laureate, bust.
8.8 gm.

The death of Constantius

Constantius died at Eboracum (York) in Britain during a campaign against the warlike tribes of the North on 25 July 306. Just before he died, Constantius conferred Imperium on his son, Flavius Valerius Constantinus (later Constantine the Great). The army commanded by Constantius wanted Constantine proclaimed Augustus to succeed his father, however, Galerius Maximian, the now de-facto senior Augustus elevated Severus to Augustus of the West (in accordance with precedent) and affirmed Constantine as Caesar of the West.

Coinage of Severus as Augustus and Constantine as Caesar

SELECTED EXAMPLE COINS:

RIC VI, Londinium, No. 46 (variant), Severus, Augustus of the West
CT (Cloke & Toone), No. 4.04.004, 26 July 306 - Spring 307, Rarity: RR


IMP SEVERVS PIVS FEL AVG ........................... GENIO POPV - LI ROMANI

Draped laureate bust.
Obverse legend variation: PIVS FEL instead of PIVS FELIX.
9.4 gm.

RIC VI, Londinium, No. 89b, Constantine, Caesar of the West
CT (Cloke & Toone), No. 5.03.004, c. November - December AD 307, Rarity: R

[Constantine coin photo][Constantine coin photo]
FL VAL CONSTANTINVS NOB C ........................... GENIO - POP ROM
PLN
in reverse exergue

Draped, laureate, bust.
Genius with head towered and loins draped.
Issued shortly after the death of Constantius following recognition as Caesar by Galerius.
9.3 gm.
.


Author note: In my opinion the Tetrarchy as conceived by Diocletian began to fall apart at this point in time. In his capacity as senior Augustus, Galerius Maximian had affirmed Severus as Augustus of the West who then, by precedent, should have selected his own Caesar. Of course, Constantius conferring Imperium on his son and Galerius Maximian subsequently affirming him as Caesar of the west threw a monkey wrench in the works and Galerius Maximian was stuck with the task of sorting it all out.

Revolt in Rome - Maxentius is "proclaimed" Augustus

On 28 October 306, the Citizens of Rome revolted against oppressive taxation and petitioned Marcus Aurelius Valerius Maxentius (Maxentius), son of retired Augustus Maximian Herculius, to assume Imperium. This he did, initially adopting the appellation of Princeps although his army subsquently proclaimed him Augustus. Maxentius persuaded his father, Maximian Herculius, to come out of retirement in order to assist him as "Senior Augustus".

RIC VI, Londinium, No. 85/90, Maximian Herculius as Augustus emerged from retirement:
CT (Cloke & Toone), No. 5.04.001, AD 307-310, Rarity: CC

[Licinius coin photo][Licinius coin photo]
DN MAXIMIANO PFS AVG ................................... GENIO - POP ROM
PLN
in reverse exergue

Severus sets out to depose Maxentius but is defeated and executed

Galerius Maximian, the de-facto senior Augustus, rejected the actions of Maxentius as illegal and persuaded Severus (because Rome was in his sphere of authority) to engage Maxentius and depose him. Early in 307 Severus commanded an army that marched south into Italy to engage Maxentius. Severus was not well served by this army that maintained loyalties to its previous commander, Maximian Herculius, and indeed many soldiers deserted Severus. The forces of Maxentius quickly defeated those of Severus who was captured and subsequently executed in Rome. Maximian Herculius thereupon set about organizing the defense of Rome against an anticipated attack by Galerius Maximian and in April traveled to Gaul seeking an alliance with Constantine, now Caesar of the West, in order to strengthen his position. The alliance was duly consummated and cemented when Constantine married the daughter of Maximian Herculius, Fausta Flavia Maxima (Fausta). Constantine assumed the title and powers of Augustus later in the year (not recognized by Galerius Maximian) after personal affirmation(?) by Maximian Herculius. There was now a legitimately appointed Augustus - Galerius Maximian, one dubiously assumptive Augustus - Maximian Herculius, and two very questionably appointed Augusti - Constantine and Maxentius. The structure of the Tetrarchy was now in shambles.

The Conference at Carnuntum - attempting to restore the Tetrarchy

In the spring of 308 Maximian Herculius had a falling out with his son, Maxentius, and left to join his now son-in-law, Constantine, in Gaul. In the autumn of 308 Galerius Maximian organized and convened a conference at Carnuntum consisting of himself, Diocletian and Maximian Herculius (as retired seniore Augusti) to discuss and resolve the "Augusti problem". Diocletian was but a shadow of his former self, both mentally and physically, due to the severe illness that befell him in 304 and consequently Galerius Maximian "ran the show" -- he was now the dominant force in the Tetrarchy. Galerius Maximian did not recognize either Constantine or Maxentius as Augustus, proposing instead that his old friend and military comrade Flavius Valerius Licinianus Licinius (Licinius), be appointed Augustus of the West to replace the deceased Severus and he obtained the concurrence of Diocletian and Maximian Herculius in this maneuver. Maxentius was declared an enemy of the state by the conferees and Maximian Herculius once more went into retirement. Galerius Maximian proposed that Constantine be recognized as Caesar of the West, although Constantine did not acquiesce.

Imperial claimants - death of Maximian Herculius & Galerius Maximian

There now followed a struggle between the Imperial Claimants: Maximian Herculius, who had again emerged from retirement as a self-proclaimed Augustus, and evidently with intentions to usurp Constantine, was defeated in battle by Constantine in 309 and committed suicide in 310 after betrayal by his daughter, Fausta, (wife of Constantine). Maximinus was proclaimed Augustus by the troops of his army in the same year.

Galerius Maximian, who now was afflicted with a fatal urinary/reproductive tract disease, retired in 308 and died a painful, lingering, death on 5 May 311.

Maximinus and Maxentius formed a Military Compact early in 312 but Maxentius was defeated and killed by the forces of Constantine during a famous battle at Milvian bridge outside Rome later that year. The forces of Maximinus were defeated by those of Licinius in 313, Maximinus committing suicide later that year. Constantine and Licinius were subsequently proclaimed co-Augusti, bringing down the curtain on this Historical Period.

RIC VI, Londinium, No. 121a, Constantine as Augustus

[Licinius coin photo][Licinius coin photo]
CONSTANTINVS PF AVG ................................... SOLI INVICTO COMITI
PLN
in reverse exergue

RIC VI, Londinium, No. 209b, Maximinus (Daia) as Augustus

[Constantine coin photo][Constantine coin photo]
IMP MAXIMINVS PF AVG ......................... GENIO POP ROM
PLN
in reverse exergue

RIC VI, Londinium, No. 209c, Licinius as Augustus

[Licinius coin photo][Licinius coin photo]
IMP LICINIVS PF AVG ................................... GENIO -- POP ROM
PLN
in reverse exergue


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