Severus Alexander in the context of "3rd century"

The Crisis of the Third Century, also known as the Military Anarchy or the Imperial Crisis, was a period in Roman history during which the Roman Empire nearly collapsed under the combined pressure of repeated foreign invasions, civil wars and economic disintegration. At the height of the crisis, the Roman state split into three distinct and competing polities. The period is usually dated between the death of Severus Alexander (235) and accession of Diocletian (284).

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.

Marcus Aurelius Antoninus (born Sextus Varius Avitus Bassianus, c. 204 – 13 March 222), better known by his posthumous nicknames Elagabalus (/ˌɛləˈɡæbələs/ EL-ə-GAB-ə-ləs) and Heliogabalus (/ˌhiːliə-, -lioʊ-/ HEE-lee-ə-, -⁠lee-oh-), was Roman emperor from 218 to 222, while he was still a teenager. His short reign was notorious for religious controversy and alleged sexual debauchery. A close relative to the Severan dynasty, he came from a prominent Syrian Arab family in Emesa (Homs), Syria, where he served as the head priest of the sun god Elagabal from a young age. After the death of his cousin, the emperor Caracalla, Elagabalus was raised to the Principate at 14 years of age in an army revolt instigated by his grandmother Julia Maesa against Caracalla's short-lived successor, Macrinus. He only posthumously became known by the Latinised name of his god.

Elagabalus is largely known from accounts by the contemporary senator Cassius Dio who was hostile to him, Herodian, who likely relied extensively on Dio, and the much later Historia Augusta. The reliability of the accounts of Cassius Dio and the Historia Augusta, particularly their most salacious elements, has been questioned. Elagabalus showed a disregard for Roman religious traditions. He brought the cult of Elagabal (including the large baetyl stone that represented the god) to Rome, making it a prominent part of religious life in the city. He forced leading members of Rome's government to participate in religious rites celebrating this deity, presiding over them in person. According to the accounts of Cassius Dio and the Augusta, he married four women, including a Vestal Virgin, in addition to lavishing favours on male courtiers they suggested to have been his lovers, and prostituted himself. His behaviour estranged the Praetorian Guard, the Senate, and the common people alike. Amidst growing opposition, at just 18 years of age he was assassinated and replaced by his cousin Severus Alexander in March 222. The assassination plot against Elagabalus was devised by Julia Maesa and carried out by disaffected members of the Praetorian Guard.

Gaius Julius Verus Maximinus "Thrax" (c. 173 – 238, also spelled as Maximin in some English modern texts) was a Roman emperor from 235 to 238. Born of Thracian origin – given the nickname Thrax ("the Thracian") – he rose up through the military ranks, ultimately holding high command in the army of the Rhine under Emperor Severus Alexander. After Severus was murdered in 235, Maximinus was proclaimed emperor by the army, beginning the Crisis of the Third Century, a 50-year period of instability and civil war. He is often remembered for his unusual height, although the veracity of this is disputed.

Maximinus was the commander of the Legio IV Italica when Severus Alexander was assassinated by his own troops in 235. The Pannonian army then elected Maximinus emperor.

Princeps (plural: Principes) is a Latin word meaning "first in time or order; the first, foremost, chief, the most eminent, distinguished, or noble; the first person". As a title, Princeps originated in the Roman Republic wherein the leading member of the Senate was designated princeps senatus. It is primarily associated with the Roman emperors as an unofficial title first adopted by Augustus (r. 27 BC – AD 14) in 27 BC. Its use in this context continued until the regime of Diocletian (r. 284–305) at the end of the third century. He preferred the title of dominus, meaning "lord" or "master". As a result, the Roman Empire from Augustus to Diocletian is termed the "principate" (principatus), and from Diocletian on the "dominate" (dominatus). Other historians define the reign of Augustus to Severus Alexander (r. 222–235) as the Principate, and the period afterwards as the "Autocracy".

The medieval title "Prince" goes back to princeps, as does the title Principal.

Lucius Cassius Dio (c. 165 – c. 235), also known as Dio Cassius (Ancient Greek: Δίων Κάσσιος Dion Kassios), was a Roman historian and senator of maternal Greek origin. He published 80 volumes of the history of ancient Rome, beginning with the arrival of Aeneas in Italy. The volumes documented the subsequent founding of Rome (753 BC), the formation of the Republic (509 BC), and the creation of the Empire (27 BC) up until 229 AD, during the reign of Severus Alexander. Written in Koine Greek over 22 years, Dio's work covers approximately 1,000 years of history.

Many of his books have survived intact, alongside summaries edited by later authors such as Xiphilinus, a Byzantine monk of the 11th century, and Zonaras, a Byzantine chronicler of the 12th century.

The Severan dynasty, sometimes called the Septimian dynasty, ruled the Roman Empire between 193 and 235.It was founded by the emperor Septimius Severus (r. 193–211) and Julia Domna, his wife, when Septimius emerged victorious from civil war of 193 - 197, which began with the Year of the Five Emperors.Their two sons, Caracalla (r. 192–217) and Geta (r. 211), ruled briefly after the death of Septimius.In 217 - 218 there was a short interruption of dynasty's control over the empire by reigns of Macrinus (r. 217–218) and his son Diadumenian (r. 218) before Julia Domna's relatives assumed power by raising her two grandnephews, Elagabalus (r. 218–222) and Severus Alexander (r. 222–235), in succession to the imperial office.

The dynasty's women, Julia Domna, the mother of Caracalla and Geta, and her sister, Julia Maesa, the mother of Julia Soaemias and Julia Mamaea, mothers of Elagabalus and Severus Alexander respectively, were all powerful augustae.They were also instrumental in securing imperial positions for their male relatives.

Julia Maesa (7 May before 160 AD – c. 224 AD) was a member of the Severan dynasty of the Roman Empire who was the grandmother of emperors Elagabalus and Severus Alexander, elder sister of empress Julia Domna, and mother of Julia Soaemias and Julia Mamaea. She wielded influence during the reigns of her grandsons as Augusta of the Empire from 218 to her death, especially on their elevation to emperors.

Born in Emesa, Syria (modern day Homs), to an Arab family of priests of the deity Elagabalus, Maesa and her sister Domna were the daughters of Julius Bassianus. Through her sister's marriage, Maesa became sister-in-law to Septimius Severus and aunt of Caracalla and Geta, who all became emperors. She married fellow Syrian Julius Avitus, who was of consular rank. They had two daughters, Soaemias and Mamaea, who became mothers of Elagabalus and Severus Alexander, respectively.

A barracks emperor (also called a "soldier emperor") was a Roman emperor who seized power by virtue of his command of the army. Barracks emperors were especially common from 235 to 284 AD, during the Crisis of the Third Century, which began with the assassination of Severus Alexander. Beginning with Maximinus Thrax, there were approximately fourteen barracks emperors in 33 years, which produced an average reign of a little over two years apiece. The resulting instability in the imperial office and the nearly-constant state of civil war and insurrection threatened to destroy the Roman Empire from within and left it vulnerable to attack from external adversaries.