Culture of ancient Rome
The Roman Empire, at its height (c. 117 CE), was the most extensive political and social structure in western civilization. By 285 CE the empire had grown too vast to be ruled from the central government at Rome and so was divided by Emperor Diocletian into a Western and an Eastern Empire. The Roman Empire began when Augustus Caesar became the first emperor of Rome (31 BCE) and ended, in the west, when the last Roman emperor, Romulus Augustulus, was deposed by the Germanic King Odoacer (476 CE). In the east, it continued as the Byzantine Empire until the death of Constantine XI and the fall of Constantinople to the Ottoman Turks in 1453 CE. The influence of the Roman Empire on western civilization was profound in its lasting contributions to virtually every aspect of western culture.
Roman usurper
Commodus, the last emperor of the Antonine dynasty, remembered by contemporaneous chronicles as an unpopular ruler notorious for his extravagance and cruelty, was assassinated in 192. Without sons to be his heir, a struggle for power immediately broke out amongst the governors of the most important provinces. Pertinax was elevated to the purple and recognized by his peers, but following his murder by a restive Praetorian Guard, Septimius Severus decided to make his bid for power and usurped the throne. Although initially a usurper, Severus managed to remain in power for the next 18 years and died a natural death while campaigning in northern Britain. The death of Severus Alexander (the last emperor of the Severan dynasty) in 235 triggered what historians call the crisis of the third century. In this period, from 235 to the accession of Diocletian and the establishment of the Tetrarchy in 286, Rome saw 28 emperors of whom only two had a natural death (from the plague). However, there were also 38 usurpers who raised revolts across the Empire, a clear sign that the security of the frontiers was not the only problem within the Roman world. Usurpation attempts were a constant worry for the emperors in this period; it was a too common method of acceding the throne. Successful usurpers were usually either provincial governors, commanders of a large grouping of Roman legions, or prefects of the Praetorian Guard, which had control of Rome, where the Imperial palace still lay.