The Roman Republic and Empire

According to tradition, Rome became a republic in 509 BC. By the end of the Republic, the city of Rome had achieved a grandeur befitting the capital of an empire dominating the whole of the Mediterranean. This grandeur increased under Caesar Augustus and his successors: if anything, the Great Fire of Rome during the reign of Nero acted as an excuse for further development.

From the early 3rd century, matters changed. Rome formally remained capital of the empire but emperors spent less and less time there. In 330, Constantine established a second capital at Constantinople, and even the later western emperors ruled from Milan or Ravenna, not Rome. However, the Senate, while stripped of most of its political power, was still socially prestigious and the Empire's conversion to Christianity made the Bishop of Rome (later called the Pope) the senior religious figure in the Western Empire. Also, the empire was now more open to external attack - Rome's first city walls for several hundred years were built in about 270, and even these did not stop the city being sacked first by Alaric in 410 and then by Geiseric in 455.