The two brothers briefly shared power after their father's death in 211, but Caracalla soon had Geta murdered by the Praetorian Guard and became sole ruler of the Roman Empire.

[4][5][1] According to the 4th-century historian Aurelius Victor in his Epitome de Caesaribus, he became known by the agnomen "Caracalla" after a Gallic hooded tunic that he habitually wore and made fashionable.

[7] Cassius Dio, who was still writing his Historia romana during Caracalla's reign,[8] generally referred to him as "Tarautas", after a famously diminutive and violent gladiator of the time, though he also calls him "Caracallus" on various occasions.

[12] In early 195, Caracalla's father Septimius Severus had himself adopted posthumously by the deified emperor (divus) Marcus Aurelius (r. 161–180); accordingly, in 195 or 196 Caracalla was given the imperial rank of Caesar, adopting the name Marcus Aurelius Antoninus Caesar, and was named imperator destinatus (or designatus) in 197, possibly on his birthday, 4 April, and certainly before 7 May.

[13][12] His brother Geta was proclaimed nobilissimus caesar on the same day, and their father Septimius Severus was awarded the victory name Parthicus Maximus.

[17][24] During the journey back from Britain to Rome with their father's ashes, Caracalla and his brother continuously argued with one another, making relations between them increasingly hostile.

[38] The edict widened the obligation for public service and gave increased revenue through the inheritance and emancipation taxes that only had to be paid by Roman citizens.

[40] The conspiracy in question was in response to Caracalla's murder of Geta and the subsequent slaughter of his followers; fratricide would only have been condoned if his brother had been a tyrant.

[39][44] During the campaign of 213–214, Caracalla successfully defeated some of the Germanic tribes while settling other difficulties through diplomacy, though precisely with whom these treaties were made remains unknown.

[44][45] While there, Caracalla strengthened the frontier fortifications of Raetia and Germania Superior, collectively known as the Agri Decumates, so that it was able to withstand any further barbarian invasions for another twenty years.

[46][47] Caracalla responded to this insult by slaughtering the unsuspecting deputation of leading citizens that had assembled before the city to greet his arrival in December 215, before setting his troops against Alexandria for several days of looting and plunder.

[48] A fragmented inscription found in the church of Sant' Agata dei Goti in Rome records the construction, or possibly restoration, of a temple dedicated to the god Serapis.

Two other inscriptions dedicated to Serapis, as well as a granite crocodile similar to one discovered at the Iseum et Serapeum, were also found in the area around the Quirinal Hill.

Pontifex Maximus, TRibunus Plebis XVIIII, COnSul IIII, Pater Patriae The expenditures that Caracalla made with the large bonuses he gave to soldiers prompted him to debase the coinage soon after his ascension.

[65] In 216, Caracalla pursued a series of aggressive campaigns in the east against the Parthians, intended to bring more territory under direct Roman control.

[67] In the following winter, Caracalla retired to Edessa, modern Şanlıurfa in south-east Turkey, and began making preparations to renew the campaign by spring.

[7] On 8 April 217 Caracalla, who had just turned 29, was travelling to visit a temple of the moon god Sin,[68] while on the road from Edessa to Carrhae, now Harran in southern Turkey, where in 53 BC the Romans had suffered a defeat at the hands of the Parthians.

[70][71] Caracalla's official portrayal as sole emperor marks a break from the detached images of the philosopher-emperors who preceded him: his close-cropped haircut is that of a soldier, his pugnacious scowl a realistic and threatening presence.

This rugged soldier-emperor, an iconic archetype, was adopted by most of the following emperors, such as Maximinus Thrax, who were dependent on the support of the troops to rule the empire.

After his death, the public made comparisons between him and other condemned emperors and called for the horse race celebrating his birthday to be abolished and for gold and silver statues dedicated to him to be melted down.

[81] Alongside this, these contemporary sources present Caracalla as a "soldier-emperor" for his preference of the soldiery over the senators, a depiction that made him even less popular with the senatorial biographers.

[82] The Historia Augusta is considered by historians as the least trustworthy for all accounts of events, historiography, and biographies among the ancient works and is full of fabricated materials and sources.

[90] An example of this hostility is found in one section where Dio notes that Caracalla is descended from three different races and that he managed to combine all of their faults into one person: the fickleness, cowardice, and recklessness of the Gauls, the cruelty and harshness of the Africans, and the craftiness that is associated with the Syrians.

In the story, after Severus' death the Romans wanted to make Geta king of Britain, but the Britons preferred Bassianus because he had a British mother.

His tyrannical career became the subject of the work of several French painters such as Greuze, Julien de Parme [fr], David, Bonvoisin, J.-A.-C. Pajou, and Lethière.

Caracalla's likeness was readily available to the painters due to the distinct style of his portraiture and his unusual soldier-like choice of fashion that distinguished him from other emperors.

Wood also notes the similarity between Caracalla and his crimes leading to his assassination and the eventual uprising against, and death of, King Louis XVI: both rulers had died as a result of their apparent tyranny.

[94] The art and linguistics historian John Agnew and the writer Walter Bidwell describe Caracalla as having an evil spirit, referring to the devastation he wrought in Alexandria.

[96][97] The historian Clifford Ando supports this description, suggesting that Caracalla's rule as sole emperor is notable "almost exclusively" for his crimes of theft, massacre, and mismanagement.

[94] Gibbon compared Caracalla to emperors such as Hadrian who spent their careers campaigning in the provinces and then to tyrants such as Nero and Domitian whose entire reigns were confined to Rome and whose actions only impacted upon the senatorial and equestrian classes residing there.