--- title: Roman Emperor author: Donald L. Wasson source: https://www.worldhistory.org/Roman_Emperor/ format: machine-readable-alternate license: Creative Commons Attribution-NonCommercial-ShareAlike (https://creativecommons.org/licenses/by-nc-sa/4.0/) updated: 2023-09-25 --- # Roman Emperor _Authored by [Donald L. Wasson](https://www.worldhistory.org/user/DWasson/)_ [Roman](https://www.worldhistory.org/disambiguation/Roman/) emperors ruled the [Roman Empire](https://www.worldhistory.org/Roman_Empire/) starting with [Augustus](https://www.worldhistory.org/augustus/) in 27 BCE and continuing in the West until the late 5th century CE and in the [Eastern Roman Empire](https://www.worldhistory.org/Byzantine_Empire/) up to the mid-15th century CE. The emperors took titles such as *[Caesar](https://www.worldhistory.org/disambiguation/caesar/)* and *Imperator* but it was their command of the army which allowed them to keep the throne. Prior to the birth of the Roman [Empire](https://www.worldhistory.org/empire/) in the latter part of the first century BCE, there had existed many empires among these were the Assyrian, the Babylonian, the Persian, and the Macedonian. All of these had great leaders such as [Cyrus](https://www.worldhistory.org/disambiguation/Cyrus/), [Darius](https://www.worldhistory.org/disambiguation/darius/), [Xerxes](https://www.worldhistory.org/Xerxes_I/), and, of course, [Alexander the Great](https://www.worldhistory.org/Alexander_the_Great/). Yet, history tells us, these great men were all called kings; the term *emperor* was never used. In contrast, the Roman Empire was different, for it didn't have a king; it had an emperor, and one must search both the [Roman Republic](https://www.worldhistory.org/Roman_Republic/) and the Empire, almost one thousand years of history, to discover the reasons for the difference. ### From The Republic to The Imperial Era Before [Rome](https://www.worldhistory.org/Rome/) was an empire, it was a republic with a long history of “democratic” rule. After ousting the [Etruscans](https://www.worldhistory.org/Etruscan_Civilization/) and their king, the [city-state](https://www.worldhistory.org/Polis/) was ruled by a Senate and/or an assembly with elected magistrates - consuls and tribunes, both with a term of office limitations. After conquering the Italian peninsula, Rome gained considerable land through an aggressive military campaign - primarily in North [Africa](https://www.worldhistory.org/disambiguation/africa/), Spain, Macedonia and [Greece](https://www.worldhistory.org/greece/), plus various islands throughout the [Mediterranean](https://www.worldhistory.org/disambiguation/mediterranean/). Unfortunately, the size of the Republic placed considerable strain on its leadership; leaders, good and bad, rose through the political and military ranks to gain power, men such as [Sulla](https://www.worldhistory.org/sulla/), Gaius, [Pompey](https://www.worldhistory.org/pompey/) and finally [Julius Caesar](https://www.worldhistory.org/Julius_Caesar/); the latter would assume the ominous title of “dictator for life.” As one historian noted, various social, political, and economic forces could no longer be contained by the Republican leadership; change was inevitable. After the [assassination of Julius Caesar](https://www.worldhistory.org/article/803/the-assassination-of-julius-caesar/) by members of the Senate on the Ides of March, a [battle](https://www.worldhistory.org/disambiguation/battle/), both political and military, ensued between the members of the so-called [Second Triumvirate](https://www.worldhistory.org/Second_Triumvirate/) ([Octavian](https://www.worldhistory.org/augustus/), [Mark Antony](https://www.worldhistory.org/Mark_Antony/) and Lepidus) with Octavian becoming the eventual victor. ### The First Emperor As a victorious general, Octavian had often heard the cries of his soldiers - “Imperator” - especially after his defeat of [Mark](https://www.worldhistory.org/disambiguation/Mark/) [Antony](https://www.worldhistory.org/Mark_Antony/). In the future, this title would automatically be assumed by his successors, regardless of their military experience, upon their ascension to the imperial throne. After two decades of civil [war](https://www.worldhistory.org/disambiguation/War/), Octavian, the adopted son of [Julius](https://www.worldhistory.org/disambiguation/Julius/) Caesar, returned to Rome a hero. The people celebrated, hoping for the return of the stability that had been the Republic. While initially shying away from honors and power, Octavian, who would soon become known by the name of Augustus (a name meaning “sacred” or “revered”), would increasingly assume authority far beyond the intent of the Senate who had inadvertently granted it. One historian raised the question: was Augustus a “tyrant” who quietly took away Roman liberty, or a generous statesman who shared power with the Senate with the consent of the people of Rome? As an emperor, Augustus would set the stage for all of those who would follow him, from [Tiberius](https://www.worldhistory.org/Tiberius/), his much-maligned stepson, through the corruption of [Caligula](https://www.worldhistory.org/Caligula/) and [Nero](https://www.worldhistory.org/Nero/), the cruelty and incompetence of [Domitian](https://www.worldhistory.org/domitian/), and lastly, to the final individual to be called a Roman emperor, [Romulus](https://www.worldhistory.org/Romulus_and_Remus/) Augustalus (oddly named for one of the mythical founders of the [city](https://www.worldhistory.org/city/) and the empire's first emperor). [ ![Augustus as Pontifex Maximus (Detail)](https://www.worldhistory.org/img/r/p/500x600/486.jpg?v=1776682637) Augustus as Pontifex Maximus (Detail) Mark Cartwright (CC BY-NC-SA) ](https://www.worldhistory.org/image/486/augustus-as-pontifex-maximus-detail/ "Augustus as Pontifex Maximus (Detail)")### Absolute Power While many of the structures that had existed under the old Republic remained, such as the Senate, they existed in name only. In a kingdom, a king had to answer to an assembly ([England](https://www.worldhistory.org/disambiguation/england/) had a Parliament; France had the Estates General, for example). Often, these assemblies controlled the finances of the kingdom, but in Rome the emperor could collect and spend as he wished. Emperor Nero, always in need of funds, would cry conspiracy, seize the property of an unsuspecting senator and murder him. After Augustus, the Senate would never again have any real authority - only to endorse the wishes of the emperor. While Augustus and his successors would treat them with a modicum of respect (most wanted to avoid a repeat of the Ides of March) the real power was in the hands of the emperor, and to ensure his own safety, he relied on his personal bodyguard – the [Praetorian Guard](https://www.worldhistory.org/Praetorian_Guard/), who, within a few decades, would wield power unforeseen even by the Emperor Augustus. With the consent of the Senate, Augustus slowly assumed the sole leadership of the Empire, and while he disliked titles (even the title of *emperor*); he took instead the title of “princeps” meaning “first citizen.” Initially, he was a [consul](https://www.worldhistory.org/Consul/) (a position other emperors would also hold) and provincial governor (of [Gaul](https://www.worldhistory.org/gaul/), [Syria](https://www.worldhistory.org/syria/), [Egypt](https://www.worldhistory.org/egypt/) and [Cyprus](https://www.worldhistory.org/cyprus/), the latter gave him control of a majority of the military); as emperor he would command twenty-six legions. The Senate bestowed on him, and thereby his successors, certain powers for life: *imperium maius*, extreme authority over the provincial governors; and *tribunicia potestas* or [tribune](https://www.worldhistory.org/Tribune/) of the plebs, the authority to call an assembly of the people to enact laws. With his new powers, he could veto the actions of the magistrates (whom he would later appoint), and, in order to control those around him, he controlled the imperial patronage - no one could “run” for office without his consent. He also interfered with the [religion](https://www.worldhistory.org/religion/) of the empire. He rebuilt decaying temples, resurrected old religious ceremonies and assumed the title of Pontifex Maximus or Chief Priest. In short, the emperor's word became [law](https://www.worldhistory.org/disambiguation/law/). However, despite his growing power, he remained popular with the people through his continuous supply of grain, games (he even presided over them) and numerous rebuilding projects. In his *The Twelve Caesars*, historian [Suetonius](https://www.worldhistory.org/Suetonius/) wrote that the emperor improved the overall appearance of the city. “I found Rome built of sun-dried bricks; I leave her clothed in marble.” Those who followed Augustus would continue to rebuild the city, especially her temples, [aqueducts](https://www.worldhistory.org/aqueduct/), and arenas. Many Roman citizens believed they were entering a new golden age. ### The Imperial Dynasties Augustus (31 BCE to 14 CE) maintained control of the empire, even in [death](https://www.worldhistory.org/disambiguation/Death/), and, like a king, named his successor. In his case it was Tiberius. Even the name Augustus would become a title, assumed by all who followed him. But the naming of a successor is one of the few ways an emperor is like a king. In a kingdom, the tradition was for the continuation of a bloodline. The present queen of England is from the House of Windsor and can trace her ancestry through the Hanoverians, Stuarts, Tudors, and even the [Plantagenets](https://www.worldhistory.org/collection/66/the-plantagenets/). [ ![The Five Good Emperors of the Roman Empire (96 - 180 CE)](https://www.worldhistory.org/img/r/p/750x750/17738.png?v=1760676978-1754457195) The Five Good Emperors of the Roman Empire (96 - 180 CE) Simeon Netchev (CC BY-NC-ND) ](https://www.worldhistory.org/image/17738/the-five-good-emperors-of-the-roman-empire-96---18/ "The Five Good Emperors of the Roman Empire (96 - 180 CE)")In contrast, the last emperor of the Roman Empire wasn't even related to his predecessor let alone Augustus. In fact, only a handful of emperors were related by blood. [Titus](https://www.worldhistory.org/disambiguation/Titus/) and Domitian were the sons of [Vespasian](https://www.worldhistory.org/Vespasian/) while [Commodus](https://www.worldhistory.org/commodus/) was the son of [Marcus Aurelius](https://www.worldhistory.org/Marcus_Aurelius/). Others were adopted - Tiberius, Nero, [Trajan](https://www.worldhistory.org/trajan/), [Hadrian](https://www.worldhistory.org/hadrian/), [Antoninus Pius](https://www.worldhistory.org/Antoninus_Pius/), and Marcus Aurelius - while [Nerva](https://www.worldhistory.org/Nerva/) was chosen by the Senate. Some obtained the throne through [conquest](https://www.worldhistory.org/warfare/) or murder - [Galba](https://www.worldhistory.org/Galba/), [Otho](https://www.worldhistory.org/Otho/), [Vitellius](https://www.worldhistory.org/Vitellius/), Vespasian, and [Macrinus](https://www.worldhistory.org/Macrinus/). One even bought the throne - [Didius Julianus](https://www.worldhistory.org/Didius_Julianus/). Surprisingly, some emperors never set foot in Rome - Macrinus and Maximinius, while at times, there might be more than one claimant such as in the Year of the Five Emperors. However an individual obtained the throne, the power that went with the position remained. And, at the forefront of this power was the Praetorian Guard. While the authority of the empire lay in the hands of the emperor, he placed his life in the hands of the Guard. During bleak times, the Praetorian Guard would be the ones to pick and choose (and sometimes overthrow) an emperor. After the death of Caligula at the hands of the Praetorian Guard, they found [Claudius](https://www.worldhistory.org/claudius/) cowering behind a curtain and hurried him to the Senate, who reluctantly proclaimed him emperor. When they had finally realized the ineptness and depravity of [Elagabalus](https://www.worldhistory.org/Elagabalus/), they murdered him and his mother and declared [Alexander Severus](https://www.worldhistory.org/Alexander_Severus/) the new emperor. [ ![Caligula with Cuirass](https://www.worldhistory.org/img/r/p/500x600/2401.jpg?v=1775039766) Caligula with Cuirass Carole Raddato (CC BY-SA) ](https://www.worldhistory.org/image/2401/caligula-with-cuirass/ "Caligula with Cuirass")Unfortunately, the life of an emperor would not always be filled attending lavish ceremonies, directing military campaigns and dictating laws. He would often sit on the throne, paranoid, fearful of those closest to him. Of the first twelve emperors - Augustus through to Nerva - four would die naturally (although some question one or two of these), four would be assassinated, two would commit suicide, and two would be murdered by poison or suffocation, as one historian put it, “supreme power brought supreme risk.” It was rare that an emperor would resign or die a natural death as the possibility of being overthrown always existed. The autocratic power of the emperor would endure despite the destructive reigns of Caligula, Nero, Commodus, and Elagabalus. Luckily for the empire, it would see the strength of such men as Vespasian, Trajan, Marcus Aurelius, and [Constantine](https://www.worldhistory.org/disambiguation/Constantine/); territories would be gained and lost; the empire would expand and contract, but somehow, despite the good and bad, the empire would continue to survive. ### Deification The emperor held a special place in the hearts and minds of the people of Rome, both in life and in death. This adoration for the imperial leader would lead to his eventual deification or apotheosis. However, this type of honor or Imperial Cult was not unique to Rome; it dated back to [Alexander](https://www.worldhistory.org/disambiguation/Alexander/) the Great - he considered himself not the son of Phillip II but the son of [Zeus](https://www.worldhistory.org/zeus/). Emperor Augustus was treated as a deity during his reign; altars and temples were built to honor him throughout the empire - [Pergamum](https://www.worldhistory.org/pergamon/), Lyons, and [Athens](https://www.worldhistory.org/Athens/) - but none were built in Rome (at least while he still lived). Although he may have considered himself the son of a [god](https://www.worldhistory.org/God/), he never permitted himself to be called a god. Upon his death, the Senate would deify him - the same would happen to many of those who followed him, for example, Antonius Pius, Hadrian, Marcus Aurelius, Trajan and Alexander Severus. Often, an emperor would initiate the deification of his predecessor. Unfortunately, emperors such as Tiberius, Caligula, Nero, Commodus, and Elagabalus were considered too “odious” to receive the honor. Caligula and Nero both considered themselves gods while they were still alive, and Commodus thought he was actually the reincarnation of [Hercules](https://www.worldhistory.org/hercules/). ### [ ![Byzantine Empire c. 460 CE](https://www.worldhistory.org/img/r/p/500x600/7704.png?v=1773840562) Byzantine Empire c. 460 CE Tataryn77 (CC BY-SA) ](https://www.worldhistory.org/image/7704/byzantine-empire-c-460-ce/ "Byzantine Empire c. 460 CE") ### Division of the Empire After a long period of truly incompetent emperors, [Diocletian](https://www.worldhistory.org/Diocletian/) came to power in 284 CE. The *[Pax Romana](https://www.worldhistory.org/Pax_Romana/)* or Roman peace had been dead for over one [hundred years](https://www.worldhistory.org/disambiguation/Hundred_Years/). The empire was being attacked on all sides and it was on the verge of collapse. Diocletian realized the one major flaw of the empire - its size. To solve the problem he created the tetarchy or rule of four. He divided the empire into two parts, one with its capital at Rome and another with its capital as Nicomedia (it would later be moved to [Byzantium](https://www.worldhistory.org/Byzantium/) or [Constantinople](https://www.worldhistory.org/Constantinople/) by Emperor Constantine). The principate initiated by Augustus was replaced by the dominate, however, he strengthened the borders, developed a more efficient bureaucracy, and stabilized the [economy](https://www.worldhistory.org/disambiguation/economy/). Unfortunately, as the eastern half of the empire flourished, the west declined, even the city of Rome fell into ruin, until, finally, in 476 CE, the last emperor surrendered. The city's conqueror, [Odoacer](https://www.worldhistory.org/Odoacer/), refused the title of emperor. ### Conclusion For the most part, the people of the Roman Empire were kept reasonably happy, even during times of duress, as long as the emperors provided grain for bread and games/entertainment. Lasting monuments were built to honor many of the emperors - the Baths of [Caracalla](https://www.worldhistory.org/Caracalla/) and Nero, the Arch of Constantine, and [Trajan's Column](https://www.worldhistory.org/Trajans_Column/). The emperor was an absolute ruler who provided stability for the people. It was never a constitutional office, quite simply, the emperor was the law. #### Editorial Review This human-authored definition has been reviewed by our editorial team before publication to ensure accuracy, reliability and adherence to academic standards in accordance with our [editorial policy](https://www.worldhistory.org/static/editorial-policy/). ## Bibliography - [Baker, S. *Ancient Rome.* BBC Books, 2007.](https://www.worldhistory.org/books/1846072840/) - [Clark, G. *Late Antiquity.* Oxford University Press, 2011.](https://www.worldhistory.org/books/0199546207/) - [Grant, M. *The Roman Emperors.* Barnes & Noble Books, 1997.](https://www.worldhistory.org/books/0760700915/) - [Gwynn, D.M. *The Roman Republic.* Oxford University Press, USA, 2012.](https://www.worldhistory.org/books/0199595119/) - [Kerrigan, M. *A Dark History.* Metro Books, 2013.](https://www.worldhistory.org/books/1435102088/) - Potter D. *The Roman Emperors.* Metro Books, 2007 - Rogers N. *The Roman Empire.* Metro Books, 2008 - [Scarre, C. *Chronicle of the Roman Emperors.* Thames & Hudson, 1995.](https://www.worldhistory.org/books/0500050775/) - [Suetonius. *The Twelve Caesars.* Penguin Classics, 2007.](https://www.worldhistory.org/books/0140455167/) ## About the Author Donald has taught Ancient, Medieval and U.S. History at Lincoln College (Normal, Illinois)and has always been and will always be a student of history, ever since learning about Alexander the Great. He is eager to pass knowledge on to his students. ## Timeline - **27 BCE - 14 CE**: Reign of [Augustus](https://www.worldhistory.org/augustus/) [Caesar](https://www.worldhistory.org/disambiguation/caesar/). [Athens](https://www.worldhistory.org/Athens/) and the [Agora](https://www.worldhistory.org/agora/) restored. - **18 Sep 14 CE - 16 Mar 37 CE**: Reign of [Roman Emperor](https://www.worldhistory.org/Roman_Emperor/) [Tiberius](https://www.worldhistory.org/Tiberius/). - **18 Mar 37 CE - 24 Jan 41 CE**: Reign of [Roman Emperor](https://www.worldhistory.org/Roman_Emperor/) [Caligula](https://www.worldhistory.org/Caligula/). - **25 Jan 41 CE - 13 Oct 54 CE**: Reign of [Roman Emperor](https://www.worldhistory.org/Roman_Emperor/) [Claudius](https://www.worldhistory.org/claudius/). - **13 Oct 54 CE - 11 Jun 68 CE**: Reign of [Roman emperor](https://www.worldhistory.org/Roman_Emperor/) [Nero](https://www.worldhistory.org/Nero/). - **68 CE - 69 CE**: [Year of the Four Emperors](https://www.worldhistory.org/Year_of_the_Four_Emperors/): Civil [war](https://www.worldhistory.org/disambiguation/War/) in [Rome](https://www.worldhistory.org/Rome/). - **8 Jun 68 CE - 15 Jan 69 CE**: Reign of [Roman Emperor](https://www.worldhistory.org/Roman_Emperor/) [Galba](https://www.worldhistory.org/Galba/). - **15 Jan 69 CE - 16 Apr 69 CE**: Reign of [Roman Emperor](https://www.worldhistory.org/Roman_Emperor/) [Otho](https://www.worldhistory.org/Otho/). - **17 Apr 69 CE - 20 Dec 69 CE**: Reign of [Roman Emperor](https://www.worldhistory.org/Roman_Emperor/) [Vitellius](https://www.worldhistory.org/Vitellius/). - **26 Dec 69 CE - 23 Jun 79 CE**: Reign of [Roman emperor](https://www.worldhistory.org/Roman_Emperor/) [Vespasian](https://www.worldhistory.org/Vespasian/). - **24 Jun 79 CE - 13 Sep 81 CE**: Reign of [Roman Emperor](https://www.worldhistory.org/Roman_Emperor/) [Titus](https://www.worldhistory.org/disambiguation/Titus/). - **14 Sep 81 CE - 18 Sep 96 CE**: Reign of [Roman Emperor](https://www.worldhistory.org/Roman_Emperor/) [Domitian](https://www.worldhistory.org/domitian/). - **18 Sep 96 CE - 27 Jan 98 CE**: Reign of [Roman Emperor](https://www.worldhistory.org/Roman_Emperor/) [Nerva](https://www.worldhistory.org/Nerva/). - **28 Jan 98 CE - 7 Aug 117 CE**: Reign of [Roman Emperor](https://www.worldhistory.org/Roman_Emperor/) [Trajan](https://www.worldhistory.org/trajan/). - **11 Aug 117 CE - 10 Jul 138 CE**: Reign of [Roman Emperor](https://www.worldhistory.org/Roman_Emperor/) [Hadrian](https://www.worldhistory.org/hadrian/). - **10 Jul 138 CE - 7 Mar 161 CE**: Reign of [Roman Emperor](https://www.worldhistory.org/Roman_Emperor/) Antonius Pius. - **10 Jul 138 CE - 9 Mar 161 CE**: Reign of [Roman Emperor](https://www.worldhistory.org/Roman_Emperor/) [Antoninus Pius](https://www.worldhistory.org/Antoninus_Pius/). - **7 Mar 161 CE - 17 Mar 180 CE**: Reign of [Roman Emperor](https://www.worldhistory.org/Roman_Emperor/) [Marcus Aurelius](https://www.worldhistory.org/Marcus_Aurelius/). - **9 Mar 161 CE - Mar 169 CE**: [Marcus Aurelius](https://www.worldhistory.org/Marcus_Aurelius/) rules with [Lucius Verus](https://www.worldhistory.org/Lucius_Verus/). - **Mar 169 CE - 177 CE**: [Marcus Aurelius](https://www.worldhistory.org/Marcus_Aurelius/) rules alone. - **177 CE - 17 Mar 180 CE**: [Marcus Aurelius](https://www.worldhistory.org/Marcus_Aurelius/) rules with [Commodus](https://www.worldhistory.org/commodus/). - **17 Mar 180 CE - 31 Dec 192 CE**: [Commodus](https://www.worldhistory.org/commodus/) rules alone. - **1 Jan 193 CE - 28 Mar 193 CE**: Reign of [Roman Emperor](https://www.worldhistory.org/Roman_Emperor/) [Pertinax](https://www.worldhistory.org/Pertinax/). - **28 Mar 193 CE - 1 Jun 193 CE**: Reign of [Roman Emperor](https://www.worldhistory.org/Roman_Emperor/) [Didius Julianus](https://www.worldhistory.org/Didius_Julianus/). - **9 Apr 193 CE - 4 Feb 211 CE**: Reign of [Roman Emperor](https://www.worldhistory.org/Roman_Emperor/) [Septimius Severus](https://www.worldhistory.org/Septimius_Severus/). - **198 CE - 209 CE**: Reign of [Caracalla](https://www.worldhistory.org/Caracalla/) with his father [Septimius Severus](https://www.worldhistory.org/Septimius_Severus/). - **209 CE - Dec 211 CE**: Reign of [Caracalla](https://www.worldhistory.org/Caracalla/) with his father [Septimius Severus](https://www.worldhistory.org/Septimius_Severus/) and his brother Geta (Feb - Dec 211 only with Geta). - **209 CE - 26 Dec 211 CE**: Reign of [Roman Emperor](https://www.worldhistory.org/Roman_Emperor/) Geta. - **Dec 211 CE - 8 Apr 217 CE**: Reign of [Roman Emperor](https://www.worldhistory.org/Roman_Emperor/) [Caracalla](https://www.worldhistory.org/Caracalla/). - **11 Apr 217 CE - 8 Jun 218 CE**: Reign of [Roman](https://www.worldhistory.org/disambiguation/Roman/) Emperors [Macrinus](https://www.worldhistory.org/Macrinus/) with his son Diadumenian. - **8 Jun 218 CE - 11 Mar 222 CE**: Reign of [Roman Emperor](https://www.worldhistory.org/Roman_Emperor/) [Elagabalus](https://www.worldhistory.org/Elagabalus/). - **13 Mar 222 CE - 18 Mar 235 CE**: Reign of [Roman Emperor](https://www.worldhistory.org/Roman_Emperor/) [Severus Alexander](https://www.worldhistory.org/Alexander_Severus/). - **Mar 235 CE - May 238 CE**: Reign of [Roman emperor](https://www.worldhistory.org/Roman_Emperor/) [Maximinus Thrax](https://www.worldhistory.org/Maximinus_Thrax/). - **238 CE - 244 CE**: Reign of [Gordian III](https://www.worldhistory.org/Gordian_Emperors/) in [Rome](https://www.worldhistory.org/Rome/). - **22 Mar 238 CE - 12 Apr 238 CE**: Reign of [Gordian I](https://www.worldhistory.org/Gordian_Emperors/) and [Gordian II](https://www.worldhistory.org/Gordian_Emperors/) in [Rome](https://www.worldhistory.org/Rome/). - **244 CE - 249 CE**: Reign of [Philip the Arab](https://www.worldhistory.org/Philip_the_Arab/) in [Rome](https://www.worldhistory.org/Rome/). - **22 Dec 245 CE**: Birth of Emperor [Diocletian](https://www.worldhistory.org/Diocletian/). - **249 CE - 251 CE**: Reign of [Decius](https://www.worldhistory.org/Decius/) in [Rome](https://www.worldhistory.org/Rome/). - **253 CE**: Reign of Aemilianus in [Rome](https://www.worldhistory.org/Rome/). - **253 CE - 260 CE**: Reign of [Roman emperor](https://www.worldhistory.org/Roman_Emperor/) [Valerian](https://www.worldhistory.org/valerian/) with his son [Gallienus](https://www.worldhistory.org/Gallienus/) as co-emperor. - **253 CE - 268 CE**: Reign of [Gallienus](https://www.worldhistory.org/Gallienus/) in [Rome](https://www.worldhistory.org/Rome/). - **Sep 270 CE - c. Sep 275 CE**: Reign of [Roman emperor](https://www.worldhistory.org/Roman_Emperor/) [Aurelian](https://www.worldhistory.org/Aurelian/). - **284 CE - 305 CE**: Reign of [Roman Emperor](https://www.worldhistory.org/Roman_Emperor/) [Diocletian](https://www.worldhistory.org/Diocletian/). - **306 CE - 337 CE**: Reign of [Roman Emperor](https://www.worldhistory.org/Roman_Emperor/) [Constantine I](https://www.worldhistory.org/Constantine_I/). ## External Links - [History vs. Augustus - Alex Gendler and Peta Greenfield](https://ed.ted.com/lessons/history-vs-augustus-alex-gendler-and-peta-greenfield) - [The Story Of Emperor Caligula, Ancient Rome's Most Infamous Leader](https://allthatsinteresting.com/caligula) - [7 Major Emperors During the Rise of the Roman Empire](https://online.norwich.edu/academic-programs/resources/7-major-emperors-during-the-rise-of-the-roman-empire ) - [List of Rulers of the Roman Empire | Lists of Rulers | Heilbrunn Timeline of Art History | The Metropolitan Museum of Art](https://www.metmuseum.org/toah/hd/roru/hd_roru.htm) - [The Good, the Bad, and the Mad: 7 Fascinating Emperors of Ancient Rome](https://mymodernmet.com/ancient-roman-emperors/) ## Cite This Work ### APA Wasson, D. L. (2018, April 30). Roman Emperor. *World History Encyclopedia*. [https://www.worldhistory.org/Roman\_Emperor/](https://www.worldhistory.org/Roman_Emperor/) ### Chicago Wasson, Donald L.. "Roman Emperor." *World History Encyclopedia*, April 30, 2018. [https://www.worldhistory.org/Roman\_Emperor/](https://www.worldhistory.org/Roman_Emperor/). ### MLA Wasson, Donald L.. "Roman Emperor." *World History Encyclopedia*, 30 Apr 2018, [https://www.worldhistory.org/Roman\_Emperor/](https://www.worldhistory.org/Roman_Emperor/). ## License & Copyright Submitted by [Donald L. Wasson](https://www.worldhistory.org/user/DWasson/ "User Page: Donald L. Wasson"), published on 30 April 2018. The copyright holder has published this content under the following license: [Creative Commons Attribution-NonCommercial-ShareAlike](https://creativecommons.org/licenses/by-nc-sa/4.0/deed.en). This license lets others remix, tweak, and build upon this content non-commercially, as long as they credit the author and license their new creations under the identical terms. When republishing on the web a hyperlink back to the original content source URL must be included. Please note that content linked from this page may have different licensing terms.