<P> In 212, during the reign of Caracalla, Roman citizenship was granted to all freeborn inhabitants of the Empire . But despite this gesture of universality, the Severan dynasty was tumultuous--an emperor's reign was ended routinely by his murder or execution--and following its collapse, the Roman Empire was engulfed by the Crisis of the Third Century, a period of invasions, civil strife, economic disorder, and plague . In defining historical epochs, this crisis is typically viewed as marking the start of the Late Roman Empire, and also the transition from Classical Antiquity to Late Antiquity . Diocletian (reigned 284--305) brought the Empire back from the brink, but declined the role of princeps and became the first emperor to be addressed regularly as domine, "master" or "lord". This marked the end of the Principate, and the beginning of the Dominate . Diocletian's reign also brought the Empire's most concerted effort against the perceived threat of Christianity, the "Great Persecution". The state of absolute monarchy that began with Diocletian endured until the fall of the Eastern Roman Empire in 1453 . </P> <P> Diocletian divided the empire into four regions, each ruled by a separate Emperor (the Tetrarchy). Confident that he fixed the disorders plaguing Rome, he abdicated along with his co-emperor, and the Tetrarchy soon collapsed . Order was eventually restored by Constantine, who became the first emperor to convert to Christianity, and who established Constantinople as the new capital of the eastern empire . During the decades of the Constantinian and Valentinian dynasties, the Empire was divided along an east--west axis, with dual power centers in Constantinople and Rome . The reign of Julian, who attempted to restore Classical Roman and Hellenistic religion, only briefly interrupted the succession of Christian emperors . Theodosius I, the last emperor to rule over both East and West, died in 395 AD after making Christianity the official religion of the Empire . </P> <P> The Western Roman Empire began to disintegrate in the early 5th century as Germanic migrations and invasions overwhelmed the capacity of the Empire to assimilate the migrants and fight off the invaders . The Romans were successful in fighting off all invaders, most famously Attila the Hun, though the Empire had assimilated so many Germanic peoples of dubious loyalty to Rome that the Empire started to dismember itself . Most chronologies place the end of the Western Roman empire in 476, when Romulus Augustulus was forced to abdicate to the Germanic warlord Odoacer . By placing himself under the rule of the Eastern Emperor, rather than naming himself Emperor as other Germanic chiefs had done, Odoacer ended the Western Empire by ending the line of Western Emperors . The eastern Empire exercised diminishing control over the west over the course of the next century . The empire in the East--known today as the Byzantine Empire, but referred to in its time as the "Roman Empire" or by various other names--ended in 1453 with the death of Constantine XI and the fall of Constantinople to the Ottoman Turks . </P> <P> Octavian, the grandnephew and adopted son of Julius Caesar, had made himself a central military figure during the chaotic period following Caesar's assassination . In 43 BC at the age of twenty he became one of the three members of the Second Triumvirate, a political alliance with Marcus Lepidus and Mark Antony . Octavian and Antony defeated the last of Caesar's assassins in 42 BC at the Battle of Philippi, although after this point, tensions began to rise between the two . The triumvirate ended in 32 BC, torn apart by the competing ambitions of its members: Lepidus was forced into exile and Antony, who had allied himself with his lover Queen Cleopatra VII of Egypt, committed suicide in 30 BC following his defeat at the Battle of Actium (31 BC) by the fleet of Octavian . Octavian subsequently annexed Egypt to the empire . </P>

Where did most of the invaders of the roman empire originate
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