Crisis of the Third Century

Crisis of the Third Century
The divided Empire in 271 AD.   Gallic Empire   Roman Empire   Palmyrene Empire
Date 235–284 AD (c. 49 years) Location Roman Empire Result Roman victory Emperor Aurelian conquers both the Palmyrene and Gallic Empires Emperor Diocletian puts an end to the civil war Start of the Diocletianic Persecution Beginning of the Tetrarchy Territorial changes Reunification of the Palmyrene and Gallic Empires into the Roman Empire Loss of parts of the Agri Decumates Dacia abandoned
Belligerents
Roman Empire[a]	Roman Breakaways Brittanic Empire Gallic Empire Palmyrene Empire	Sasanian Empire Germanic Tribes Goths Alemanni Vandals Carpians
Commanders and leaders
Gallienus X Claudius II # Aurelian X Diocletian	Postumus X Marius X Victorinus X Tetricus I  Odaenathus X Vaballathus  Zenobia  Antiochus	Shapur I Cniva †

The Crisis of the Third Century, also known as the Military Anarchy^[1] or the Imperial Crisis (235–284), was a period in Roman history during which the Roman Empire had nearly collapsed under the combined pressure of repeated foreign invasions, civil wars and economic disintegration. At the height of the crisis, the Roman state had split into three distinct and competing polities.

The crisis began in 235 with the assassination of Emperor Severus Alexander by his own troops. During the following years, the empire saw barbarian invasions and migrations into Roman territory, civil wars, peasant rebellions and political instability, with multiple usurpers competing for power. This led to the debasement of currency and a breakdown in both trade networks and economic productivity, with the Plague of Cyprian contributing to the disorder. Roman armies became more reliant over time on the growing influence of the barbarian mercenaries known as foederati. Roman commanders in the field, although nominally loyal to the state, became increasingly independent of Rome's central authority.

During the crisis, there were at least 26 claimants to the title of emperor, mostly prominent Roman generals, who assumed imperial power over all or part of the empire. The same number of men became accepted by the Roman Senate as emperor during this period and so became legitimate emperors. By 268, the empire had split into three competing states: the Gallic Empire (including the Roman provinces of Gaul, Britannia and, briefly, Hispania); the Palmyrene Empire (including the eastern provinces of Syria Palaestina and Aegyptus); and, between them, the Italian-centered Roman Empire proper.

The reign of Aurelian (270–275) marks a turning point in the crisis period. Aurelian successfully reunited the empire by defeating the two breakaway states, and carried out a series of reforms which helped restore some measure of stability to the Roman economy. The crisis is said to have ended with Diocletian and his restructuring of the Roman imperial government, economy and military. The last is seen as a pivotal moment in Roman history, signaling the beginning of the Dominate.

The crisis resulted in such profound changes in the empire's institutions, society, economic life, and religion that it is increasingly seen by most historians as defining the transition between the historical periods of classical antiquity and late antiquity.^[2]

The army required larger and larger bribes to remain loyal.^[3] Septimius Severus raised the pay of legionaries, and gave substantial donativum to the troops.^[4][5] The large and ongoing increase in military expenditure caused problems for all of his successors.^[6] His son Caracalla raised the annual pay and lavished many benefits on the army in accordance with the advice of his father to keep their loyalty,^[7][8][9] and considered dividing the empire into eastern and western sectors with his brother Geta to reduce the conflict in their co-rule. But with the major influence of their mother, Julia Domna, this division of the empire was not possible.^[10]

Instead of warring in foreign lands, the Roman empire was increasingly put on the defensive by marauding enemies and civil wars. This cut off the essential source of income gained from plundering enemy countries, while opening up the Roman countryside to economic devastation from looters both foreign and domestic. Frequent civil wars contributed to depletion of the army's manpower, and drafting replacement soldiers strained the labour force further. Fighting on multiple fronts, increasing size and pay of the army, increasing cost of transport, populist "bread and circuses" political campaigns, inefficient and corrupt tax collection, unorganised budgeting, and paying off foreign nations for peace all contributed to financial crisis. The emperors responded by confiscating assets and supplies to combat the deficit.^[11]

The situation of the Roman Empire became dire in 235. Many Roman legions had been defeated during a previous campaign against Germanic peoples raiding across the borders, while the emperor Severus Alexander had been focused primarily on the dangers from the Sassanid Empire. Leading his troops personally, the emperor resorted to diplomacy and accepting tribute to pacify the Germanic chieftains quickly, rather than military conquest. According to Herodian this cost Severus Alexander the respect of his troops, who may have felt that more severe punishment was required for the tribes that had intruded on Rome's territory.^[12] The troops assassinated Severus Alexander and proclaimed the new emperor to be Maximinus Thrax, commander of one of the legions present.

Maximinus was the first of the barracks emperors – rulers who were elevated by the troops without having any political experience, a supporting faction, distinguished ancestors, or a hereditary claim to the imperial throne. As their rule rested on military might and generalship, they operated as warlords reliant on the army to maintain power. Maximinus continued the campaigns in Germania but struggled to exert his authority over the whole empire. The Senate was displeased at having to accept a peasant as Emperor.^[13] This precipitated the chaotic Year of the Six Emperors during which all of the original claimants were killed: in 238 a revolt broke out in Africa led by Gordian I and Gordian II,^[14] which was soon supported by the Roman Senate,^[15] but this was quickly defeated with Gordian II killed and Gordian I committing suicide. The Senate, fearing Imperial wrath,^[16] raised two of their own as co-Emperors, Pupienus and Balbinus, with Gordian I's grandson Gordian III as Caesar.^[17] Maximinus marched on Rome but was assassinated by his Legio II Parthica, and subsequently Pupienus and Balbinus were murdered by the Praetorian Guard.

In the following years, numerous Roman generals fought each other for control of the empire and neglected their duties of defending it from invasion. There were frequent raids across the Rhine and Danube frontier by foreign tribes, including the Carpians, Goths, Vandals, and Alamanni, and attacks from Sassanids in the east. Climate changes and a sea level rise disrupted the agriculture of what is now the Low Countries, forcing tribes residing in the region to migrate into Roman lands.^[18] Further disruption arose in 251, when the Plague of Cyprian (possibly smallpox) broke out. This plague caused large-scale death, severely weakening the empire.^[19][20] The situation was worsened in 260 when the emperor Valerian was captured in battle by the Sassanids (he later died in captivity).

Throughout the period, numerous usurpers claimed the imperial throne. In the absence of a strong central authority, the empire broke into three competing states. The Roman provinces of Gaul, Britain, and Hispania broke off to form the Gallic Empire in 260. The eastern provinces of Syria, Palestine, and Aegyptus also became independent as the Palmyrene Empire in 267. The remaining provinces, centered on Italy, stayed under a single ruler but now faced threats on every side.^[21]

An invasion of Macedonia and Greece by Goths, who had been displaced from their lands on the Black Sea, was defeated by emperor Claudius II Gothicus at the Battle of Naissus in 268 or 269. Historians see this victory as the turning point of the crisis. In its aftermath, a series of tough, energetic barracks emperors were able to reassert central authority. Further victories by Claudius Gothicus drove back the Alamanni and recovered Hispania from the Gallic Empire. He died of the plague in 270 and was succeeded by Aurelian, who had commanded the cavalry at Naissus. Aurelian reigned (270–275) through the worst of the crisis, gradually restoring the empire. He defeated the Vandals, Visigoths, Palmyrene Empire, and finally the remainder of the Gallic Empire. By late 274, the Roman Empire had been reunited into a single entity. However, Aurelian was assassinated in 275, sparking a further series of competing emperors with short reigns. The situation did not stabilize until Diocletian, himself a barracks emperor, took power in 284.^[22]

More than a century would pass before Rome again lost military ascendancy over its external enemies. However, dozens of formerly thriving cities, especially in the Western Empire, had been ruined. Their populations dead or dispersed, these cities could not be rebuilt, due to the economic breakdown caused by constant warfare. The economy was also crippled by the breakdown in trading networks and the debasement of the currency. Major cities and towns, including Rome itself, had not needed fortifications for many centuries, but now surrounded themselves with thick walls.^[23]

Fundamental problems with the empire still remained. The right of imperial succession had never been clearly defined, which was a factor in the continuous civil wars as competing factions in the military, Senate, and other parties put forward their favored candidate for emperor. The sheer size of the empire, which had been an issue since the late Roman Republic three centuries earlier, continued to make it difficult for a single ruler to effectively counter multiple threats at the same time. These continuing problems were addressed by the radical reforms of Diocletian, who broke the cycle of usurpation. He began by sharing his rule with a colleague, then formally established the Tetrarchy of four co-emperors in 293.^[24] However the trend of civil war would continue after the abdication of Diocletian in the Civil wars of the Tetrarchy (306–324) until the rise of Constantine the Great as sole Emperor.^[25] The empire survived until 476 in the West and until 1453 in the East.

From the beginning of the Principate there were no clear rules for the imperial succession, largely because the empire maintained the facade of a republic.^[26]

During the early Principate, the process for becoming an emperor relied on a combination of proclamation by the Senate, popular approval, and acceptance by the army, in particular the Praetorian Guard. A family connection to a previous emperor was beneficial, but it did not determine the issue in the way a formal system of hereditary succession would. From the Julio-Claudian dynasty onwards there was sometimes tension between the Senate's preferred choice and the army. As the Senatorial class declined in political influence and more generals were recruited from the provinces, this tension increased.

Whenever the succession appeared uncertain, there was an incentive for any general with support of a sizable army to attempt to seize power, sparking civil war. The most recent example of this prior to the Crisis was the Year of the Five Emperors which resulted in the victory of Septimius Severus. After the overthrow of the Severan dynasty, for the rest of the 3rd century, Rome was ruled by a series of generals, coming into power through frequent civil wars which devastated the empire.^[27]

The first and most immediately disastrous of the natural disasters that the Roman Empire faced during the Third Century was the plague. The Antonine Plague that preceded the Crisis of the Third Century sapped manpower from Roman armies and proved disastrous for the Roman economy.^[28] From 249 to 262, the Plague of Cyprian devastated the Roman Empire to such a degree that some cities, such as the city of Alexandria, experienced a 62% decline in population.^[29] These plagues greatly hindered the Roman Empire's ability to ward off barbarian invasions but also factored into problems such as famine, with many farms becoming abandoned and unproductive.^[30]

A second and longer-term natural disaster that took place during the third century was the increased variability of weather. Drier summers meant less agricultural productivity and more extreme weather events led to agricultural instability. This could also have contributed to the increased barbarian pressure on Roman borders, as they too would have experienced the detrimental effects of climate change and sought to push inward to more productive areas of the Mediterranean region.^[31]

Barbarian invasions came in the wake of civil war, plague, and famine. Distress caused in part by the changing climate led various barbarian tribes to push into Roman territory. Other tribes coalesced into more formidable entities (notably the Alamanni and Franks), or were pushed out of their former territories by more dangerous peoples such as the Sarmatians (the Huns did not appear west of the Volga for another century). Eventually, the frontiers were stabilized by the Illyrian Emperors. However, barbarian migrations into the empire continued in greater and greater numbers. Though these migrants were initially closely monitored and assimilated, later tribes eventually entered the Roman Empire en masse with their weapons, giving only token recognition of Roman authority.^[32]

The defensive battles that Rome had to endure on the Danube since the 230s, however, paled in comparison to the threat the empire faced in the East. There, Sassanid Persia represented a far greater danger to Rome than the isolated attacks of Germanic tribes.^[33] The Sassanids had in 224 and 226 overthrown the Parthian Arsacids, and the Persian King Ardashir I, who also wanted to prove his legitimacy through military successes, had already penetrated into Roman territory at the time of Severus Alexander, probably taking the strategically important cities of Nisibis and Carrhae in 235/236.^[34]

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Internally, the empire faced hyperinflation caused by years of coinage devaluation.^[35] This had started earlier under the Severan emperors who enlarged the army by one quarter,^{[36][self-published source?]} and doubled the base pay of legionaries. As each of the short-lived emperors took power, they needed ways to raise money quickly to pay the military's "accession bonus" and the easiest way to do so was by inflating the coinage severely, a process made possible by debasing the coinage with bronze and copper.

This resulted in runaway rises in prices, and by the time Diocletian came to power, the old coinage of the Roman Empire had nearly collapsed. Some taxes were collected in kind and values often were notional, in bullion or bronze coinage. Real values continued to be figured in gold coinage, but the silver coin, the denarius, used for 300 years, was gone (1 pound of gold = 40 gold aurei = 1,000 denarii = 4,000 sestertii).^{[citation needed]} This currency had almost no value by the end of the third century, and trade was carried out without retail coinage.

One of the most profound and lasting effects of the Crisis of the Third Century was the disruption of Rome's extensive internal trade network. Ever since the Pax Romana, starting with Augustus, the empire's economy had depended in large part on trade between Mediterranean ports and across the extensive road systems to the Empire's interior. Merchants could travel from one end of the empire to the other in relative safety within a few weeks, moving agricultural goods produced in the provinces to the cities, and manufactured goods produced by the great cities of the East to the more rural provinces.

Large estates produced cash crops for export and used the resulting revenues to import food and urban manufactured goods. This resulted in a great deal of economic interdependence among the empire's inhabitants. The historian Henry St. Lawrence Beaufort Moss describes the situation as it stood before the crisis:

Along these roads passed an ever-increasing traffic, not only of troops and officials but of traders, merchandise and even tourists. An interchange of goods between the various provinces rapidly developed, which soon reached a scale unprecedented in the previous history and not repeated until a few centuries ago. Metals mined in the uplands of Western Europe, hides, fleeces, and livestock from the pastoral districts of Britain, Spain, and the shores of the Black Sea, wine and oil from Provence and Aquitaine, timber, pitch and wax from South Russia and northern Anatolia, dried fruits from Syria, marble from the Aegean coasts, and – most important of all – grain from the wheat-growing districts of North Africa, Egypt, and the Danube Valley for the needs of the great cities; all these commodities, under the influence of a highly organized system of transport and marketing, moved freely from one corner of the Empire to the other.^[37]

With the onset of the Crisis of the Third Century, however, this vast internal trade network broke down. The widespread civil unrest made it no longer safe for merchants to travel as they once had, and the financial crisis that struck made exchange very difficult with the debased currency. This produced profound changes that, in many ways, foreshadowed the very decentralized economic character of the coming Middle Ages.^[38]

Large landowners, no longer able to successfully export their crops over long distances, began producing food for subsistence and local barter. Rather than import manufactured goods from the empire's great urban areas, they began to manufacture many goods locally, often on their own estates, thus beginning the self-sufficient "house economy" that would become commonplace in later centuries, reaching its final form in the manorialism of the Middle Ages. The common, free people of the Roman cities, meanwhile, began to move out into the countryside in search of food and better protection.^[39]

Made desperate by economic necessity, many of these former city dwellers, as well as many small farmers, were forced to give up hard-earned basic civil rights in order to receive protection from large land-holders. In doing so, they became a half-free class of Roman citizen known as coloni. They were tied to the land, and in later Imperial law, their status was made hereditary. This provided an early model for serfdom, the origins of medieval feudal society and of the medieval peasantry. The decline in commerce between the imperial provinces put them on a path toward increased self-sufficiency. Large landowners, who had become more self-sufficient, became less mindful of Rome's central authority, particularly in the Western Empire, and were downright hostile toward its tax collectors. The measure of wealth at this time began to have less to do with wielding urban civil authority and more to do with controlling large agricultural estates in rural regions since this guaranteed access to the only economic resource of real value – agricultural land and the crops it produced. The common people of the empire lost economic and political status to the land-holding nobility, and the commercial middle classes waned along with their trade-derived livelihoods. The Crisis of the Third Century thus marked the beginning of a long gradual process that would transform the ancient world of classical antiquity into the medieval one of the Early Middle Ages.^[40]

However, although the burdens on the population increased, especially the lower strata of the population, this cannot be generalized to the whole empire, especially since living conditions were not uniform. Although the structural integrity of the economy suffered from the military conflicts of that time and the inflationary episode of the 270s, it did not collapse, especially because of the complex regional differences. Recent research has shown that there were regions that prospered even further, such as Egypt, Africa and Hispania. But even for Asia Minor, which was directly affected by attacks, no general decline can be observed.^[41] While commerce and the overall economy flourished in several regions, with several provinces not affected by hostilities, other provinces experienced some serious problems, as evidenced by personal hoards in the northwestern provinces of the empire. However, there can be no talk of a general economic crisis throughout the whole of Empire.^[42]

Even the Roman cities began to change in character. The large cities of classical antiquity slowly gave way to the smaller, walled cities that became common in the Middle Ages. These changes were not restricted to the third century, but took place slowly over a long period, and were punctuated with many temporary reversals. In spite of extensive reforms by later emperors, however, the Roman trade network was never able to fully recover to what it had been during the Pax Romana (27 BC – AD 180). This economic decline was far more noticeable and important in the western part of the empire, which was also invaded by barbarian tribes several times during the century. Hence, the balance of power clearly shifted eastward during this period, as evidenced by the choice of Diocletian to rule from Nicomedia in Asia Minor, putting his second in command, Maximian, in Milan. This would have a considerable impact on the later development of the empire with a richer, more stable eastern empire surviving the end of Roman rule in the west.^[43]

While imperial revenues fell, imperial expenses rose sharply. More soldiers, greater proportions of cavalry, and the ruinous expense of walling in cities all added to the toll. Goods and services previously paid for by the government were now demanded in addition to monetary taxes. The empire suffered from a crippling labour shortage. The steady exodus of both rich and poor from the cities and now-unprofitable professions forced Diocletian to use compulsion; conscription was made universal, most trades were made hereditary, and workers could not legally leave their jobs or travel elsewhere to seek better-paying ones. This included the unwanted middle-class civil service positions and under Constantine, the military. Constantine also tried to provide social programs for the poor to reduce the labour shortage.^[44]

All the barracks emperors based their power on the military and on the soldiers of the field armies, not on the Praetorians in Rome. Thus, Rome lost its role as the political center of the empire during the third century, although it remained ideologically important. In order to legitimize and secure their rule, the emperors of the third century needed above all military successes.^[45]

The centre of decision-making shifted away from Rome and to wherever the emperor was with his armies, typically, in the east. This led to the transfer of the capital to the four cities Milan, Trier, Nicomedia, and Sirmium, and then to Constantinople. The Senate ceased to be the main governing organ and instead members of the equestrian class who filled the military officer corps became increasingly prominent.^[46]

Several emperors who rose to power through acclamation of their troops attempted to create stability by giving their descendants the title of Augustus and so making them co-emperors who later succeeded to the throne after their death or on some occasions their relatives managed to become an emperor immediately after their death. This led to the creation of several brief dynasties.

Portrait	Name	Birth	Succession	Reign	Death	Time in office
	Maximinus Thrax CAESAR GAIVS IVLIVS VERVS MAXIMINVS AVGVSTVS	c. AD 173, Thracia	Proclaimed emperor by Pannonian legions after Severus Alexander's assassination	c. March 235 – June 238	June AD 238 (aged 65) Assassinated by his own troops	3 years

Portrait	Name	Birth	Succession	Reign	Death	Time in office
	Gordian I CAESAR MARCVS ANTONIVS GORDIANVS SEMPRONIANVS AFRICANVS AVGVSTVS	c. AD 159, Phrygia?	Proclaimed emperor, whilst Pro-consul in Africa, during a revolt against Maximinus Thrax. Ruled jointly with his son Gordian II, and in opposition to Maximinus. Technically a usurper, but retrospectively legitimized by the accession of Gordian III	c. March – April 238	April AD 238 Committed suicide upon hearing of the death of Gordian II	22 days
	Gordian II CAESAR MARCVS ANTONIVS GORDIANVS SEMPRONIANVS ROMANVS AFRICANVS AVGVSTVS	c. AD 192, ?	Proclaimed emperor, alongside father Gordian I, in opposition to Maximinus by act of the Senate	c. March – April 238	April AD 238 Killed during the Battle of Carthage, fighting a pro-Maximinus army	22 days
	Pupienus (non-dynastic) CAESAR MARCVS CLODIVS PVPIENVS MAXIMVS AVGVSTVS	c. AD 178, ?	Proclaimed joint emperor with Balbinus by the Senate in opposition to Maximinus	c. April – July 238	July 29, AD 238 Assassinated by the Praetorian Guard	99 days
	Balbinus (non-dynastic) CAESAR DECIMVS CAELIVS CALVINVS BALBINVS PIVS AVGVSTVS	?	Proclaimed joint emperor with Pupienus by the Senate after death of Gordian I and II, in opposition to Maximinus	c. April – July 238	July 29, AD 238 Assassinated by Praetorian Guard	99 days
	Gordian III CAESAR MARCVS ANTONIVS GORDIANVS AVGVSTVS	January 20, AD 225, Rome	Proclaimed emperor by supporters of Gordian I and II, then by the Senate; caesar with Pupienus and Balbinus until July AD 238. Grandson of Gordian I	c. July 238 – February 244	February 11, AD 244 Unknown; possibly murdered on orders of Philip I	5 years, 7 months

Portrait	Name	Birth	Succession	Reign	Death	Time in office
	Philip the Arab CAESAR MARCVS IVLIVS PHILIPPVS AVGVSTVS with Philip II MARCVS IVLIVS SEVERVS PHILLIPVS AVGVSTVS	c. AD 204, Shahba, Syria	Praetorian Prefect to Gordian III, took power after his death; made his son Philip II co-emperor in summer AD 247	c. February 244 – September 249	September/October AD 249 (aged 45) Killed in the Battle of Verona by Decius	5 years, 7 months
	Silbannacus IMPERATOR MAR. SILBANNACHVS AVGVSTVS	?	Unknown, but he may have been a usurper.	Unknown, possibly between c. 238 and c. 260	?	Unknown, likely very short

Portrait	Name	Birth	Succession	Reign	Death	Time in office
	Trajan Decius CAESAR GAIVS MESSIVS QVINTVS TRAIANVS DECIVS AVGVSTVS with Herennius Etruscus	c. AD 201, Budalia, Pannonia Inferior	Governor under Philip I; proclaimed emperor by Danubian legions then defeating and killing Philip in the Battle of Verona; made his son Herennius Etruscus co-emperor in early AD 251	c. September 249 – June 251	June AD 251 Both killed in the Battle of Abrittus fighting against the Goths	2 years
	Hostilian CAESAR CAIVS VALENS HOSTILIANVS MESSIVS QVINTVS AVGVSTVS	Sirmium	Son of Trajan Decius, accepted as heir by the Senate	c. June 251 – late 251	September/October AD 251 Natural causes (plague)	4–5 months

Portrait	Name	Birth	Succession	Reign	Death	Time in office
	Trebonianus Gallus CAESAR GAIVS VIBIVS TREBONIANVS GALLVS AVGVSTVS with Volusianus GAIVS VIBIVS VOLVSIANVS AVGVSTVS	AD 206, Italia	Governor of Moesia Superior, proclaimed emperor by Danubian legions after Decius's death (and in opposition to Hostilian); made his son Volusianus co-emperor in late AD 251.	c. June 251 – August 253	August AD 253 (aged 47) Assassinated by their own troops, in favor of Aemilian	2 years
	Aemilian CAESAR MARCVS AEMILIVS AEMILIANVS AVGVSTVS	c. AD 207 or 213 Africa	Governor of Moesia Superior, proclaimed emperor by Danubian legions after defeating the Goths; accepted as emperor after death of Gallus	c. August – October 253	September/October AD 253 (aged 40 or 46) Assassinated by his own troops, in favor of Valerian	2 months

Portrait	Name	Birth	Succession	Reign	Death	Time in office
	Valerian CAESAR PVBLIVS LICINIVS VALERIANVS AVGVSTVS	c. AD 195	Governor of Noricum and Raetia, proclaimed emperor by Rhine legions after death of Gallus; accepted as emperor after death of Aemilian	c. October 253 – 260	After AD 260 Captured in Battle of Edessa against Persians, died in captivity	7 years
	Gallienus CAESAR PVBLIVS LICINIVS EGNATIVS GALLIENVS AVGVSTVS with Saloninus	AD 218	Son of Valerian, made co-emperor in AD 253; his son Saloninus is very briefly co-emperor in c. July 260 before assassination by Postumus	c. October 253 – September 268	September AD 268 Murdered at Aquileia by his own commanders	15 years

Portrait	Name	Birth	Succession	Reign	Death	Time in office
	Claudius II CAESAR MARCVS AVRELIVS CLAVDIVS AVGVSTVS	May 10, AD 210, Sirmium	Victorious general at Battle of Naissus, seized power after Gallienus's death According to Epitome de Caesaribus he was a bastard son of Gordian II	c. September 268 – January/April 270	January/April AD 270 (aged 60) Natural causes (plague)	1 year, 4–7 months
	Quintillus CAESAR MARCVS AVRELIVS CLAVDIVS QVINTILLVS AVGVSTVS	c. AD 210, Sirmium	Brother of Claudius II, seized power after his death	c. April–May (?) 270	AD 270 (aged around 60) Unclear; possibly suicide or murder	17–77 days

Portrait	Name	Birth	Succession	Reign	Death	Time in office
	Aurelian CAESAR LVCIVS DOMITIVS AVRELIANVS AVGVSTVS	September 9, AD 214/AD 215, Sirmium	Proclaimed emperor by Danubian legions after Claudius II's death, in opposition to Quintillus	c. May 270 – October 275	September AD 275 (aged 60–61) Assassinated by Praetorian Guard	5 years

Portrait	Name	Birth	Succession	Reign	Death	Time in office
	Tacitus CAESAR MARCVS CLAVDIVS TACITVS AVGVSTVS	c. 200, Interamna Nahars, Italia	Elected by the Senate to replace Aurelian, after a short interregnum	c. December 275 – June 276	June AD 276 (aged 76) Natural causes (fever), possibly assassinated	9 months
	Florianus CAESAR MARCVS ANNIVS FLORIANVS AVGVSTVS	?	Brother of Tacitus, elected by the army in the west to replace him	c. June 276 – September 276	September? AD 276 (aged ?) Assassinated by his own troops, in favor of Probus	3 months

Portrait	Name	Birth	Succession	Reign	Death	Time in office
	Probus CAESAR MARCVS AVRELIVS PROBVS AVGVSTVS	AD 232, Sirmium	Governor of the eastern provinces, proclaimed emperor by Danubian legions in opposition to Florian	c. September 276 – September AD 282	September/ October AD 282 (aged 50) Assassinated by his own troops, in favor of Carus	6 years

Portrait	Name	Birth	Succession	Reign	Death	Time in office
	Carus CAESAR MARCVS AVRELIVS CARVS AVGVSTVS	c. AD 230, Narbo, Gallia Narbonensis	Praetorian Prefect to Probus; seized power either before or after Probus was murdered; made his son Carinus co-emperor in early AD 283	c. September 282 – July/August 283	July/August AD 283 Natural causes? (Possibly killed by lightning)	10–11 months
	Numerian CAESAR MARCVS AVRELIVS NVMERIVS NVMERIANVS AVGVSTVS	?	Son of Carus, succeeded him jointly with his brother Carinus	c. July/August 283 – November 284	AD 284 Unclear; possibly assassinated	1 year
	Carinus CAESAR MARCVS AVRELIVS CARINVS AVGVSTVS	?	Son of Carus, ruled shortly with him and then with his brother Numerian	Spring 283– July 285	July AD 285 Died in the Battle of the Margus	2 years

• Bagaudae
• Sengoku period – a similar period in Japanese history
• Warring States period and Three Kingdoms period – similar periods in Chinese history (the latter roughly contemporaneous with the Crisis of the Third Century)
• Jublains archeological site documents some effects of the crisis in what is now western France
• Barbarian invasions of the 3rd century
• Low Roman Empire

• Allen, Larry (2009). The Encyclopedia of Money (2nd ed.). Santa Barbara, CA: ABC-CLIO. pp. 346–348. ISBN 978-1598842517.
• Davies, Glyn (1997) [1994]. A History of Money: From Ancient Times to the Present Day (Reprint ed.). Cardiff: University of Wales Press. pp. 95–99. ISBN 978-0708313510.
• Olivier Hekster, Rome and Its Empire, AD 193–284 (Edinburgh, 2008). ISBN 978 0 7486 2303 7.
• Klaus-Peter Johne (ed.), Die Zeit der Soldatenkaiser (Akademie Verlag, Berlin 2008).
• Lot, Ferdinand. End of the Ancient World and the Beginnings of the Middle Ages (Harper Torchbooks Printing, New York, 1961. First English printing by Alfred A. Knopf, Inc., 1931).
• Moss, H. St. L. B. The Birth of the Middle Ages (Clarendon Press, 1935, reprint Oxford University Press, January 2000). ISBN 0-19-500260-1.
• Watson, Alaric. Aurelian and the Third Century (Taylor & Francis, 2004) ISBN 0-415-30187-4
• White, John F. Restorer of the World: The Roman Emperor Aurelian (Spellmount, 2004) ISBN 1-86227-250-6

• Crisis of the Third Century, Hugh Kramer.
• Map, University of Calgary.
• The Crisis of the Third Century, OSU.