Roman Empire

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. It was, at the time, the largest city in the world. Estimates of its peak population range from 450,000 to over 3.5 million people with estimates of 1 to 2 million being most popular with historians.[33] This grandeur increased under Augustus, who completed Caesar's projects and added many of his own, such as the Forum of Augustus and the Ara Pacis. He is said to have remarked that he found Rome a city of brick and left it a city of marble. Augustus' successors sought to emulate his success in part by adding their own contributions to the city. In AD 64, during the reign of Nero, the Great Fire of Rome left much of the city destroyed, but in many ways it was used as an excuse for new development.[34][35]

Rome was a subsidised city at the time, with roughly 15 to 25 percent of its grain supply being paid by the central government. Commerce and industry played a smaller role compared to that of other cities like Alexandria. This meant that Rome had to depend upon goods and production from other parts of the Empire to sustain such a large population. This was mostly paid by taxes that were levied by the Roman government. If it had not been subsidised, Rome would have been significantly smaller.