After a series of civil wars, the Roman Republic destabilized and the Empire arose out of it. Formally speaking, the Republic was never truly abolished, it merely transitioned into an Empire. The events that eventually caused the Republic to become an Empire include the rise of Julius Caesar in 44 B.C., the Battle of Actium in 31 B.C., and Octavian becoming “Augustus” in 27 B.C.

In its beginning, the Empire enjoyed a period of peace, unprecedented prosperity and stability. The Empire kept expanding its territorial boundaries up until Trajan’s rule. In the 3rd century, it started to experience calamity and crises, though it was able to unify and stabilize under Diocletian and Aurelian. In the 4th century, Christianity became the dominant religion and the Empire started to split between two different rules: the Latin West and the Greek East. Finally, in the 5th century, the Western Roman Empire collapsed, however the eastern half continued to exist (the Byzantine Empire).

27 BC – 68 AD	The emperors of this period were known as part of the Julian-Claudian Dynasty. They included Augustus Caesar, Tiberius, Caligula, Claudius, and Nero. Prominent events include Varus losing his legions, Sejanus’ reign of terror, and the great fire in Rome.
68 – 69 AD	During this time four emperors ruled in quick succession. It was known as the Year of the Four Emperors: Galbo, Otho and Vitellius, then Vespasian who established the Flavian Dynasty.
69 – 96 AD	The Flavian Dynasty ruled. First was Vespasian, then his sons Titus and Domitian after. Prominent events during this time include the Jerusalem’s destruction, the construction of the Colosseum, and the eruption of Vesuvius.
96 – 192 AD	This era was known for the Five Good Emperors and the Nervan/Antonine Dynasty, which included Nerva, Trajan, Hadrian, Antoninus Pius, and Marcus Aurelius. Commodus, son of Aurelius, also became emperor. Prominent events include the construction of Pantheon in Rome, Hadrian’s Wall in Britain, and the plague that broke out in Rome.
193 – 235 AD	The Severan Dynasty ruled. The emperors were Septimius Severus, Caracalla, Geta, Macrinus, Diadumenian, Elagabus, and Alexander Severus. The Severan Dynasty was known to be the end of Rome’s era of peace.
235 – 284 AD	This era was known as the Crisis of the 3rd Century, a period of military anarchism in which no emperor would die of natural causes. They were known as “barracks emperors.” Every emperor had been a military general who rose to power through usurping power from others. The government was unstable and the economy was failing. Taxation was very high. Prominent events include civil wars, revolts, barbarian invasions, famines, earthquakes, and fires.
285 AD	Diocletian split the empire into two—the Western Roman Empire and the Byzantine (Eastern Roman) Empire.
285 – 364 AD	The Constantinian Dynasty was dominant. Constantine the Great drafted a policy of tolerance towards Christianity. The capital of the Roman Empire was relocated to Constantinople.
394 – 476 AD	The Valentinian Dynasty was dominant. The Western Roman Empire eventually became overrun by the Visigoths and Vandals (Germanic barbarians).