Rome must be considered one of the most successful imperial powers in history. In the course of centuries Rome grew from a small town on the Tiber River in central Italy into a vast empire that ultimately embraced England, all of continental Europe west of the Rhine and south of the Danube, most of Asia west of the Euphrates, northern Africa, and the islands of the Mediterranean. Unlike the Greeks, who excelled in intellectual and artistic endeavors, the Romans achieved greatness in their military, political, and social institutions. Roman society, during the republic, was governed by a strong military ethos. While this helps to explain the incessant warfare, it does not account for Rome's success as an imperial power. Unlike Greek city-states, which excluded foreigners and subjected peoples from political participation, Rome from its beginning incorporated conquered peoples into its social and political system. Allies and subjects who adopted Roman ways were eventually granted Roman citizenship.
Given the extent of its empire, the impact of Rome is especially meaningful and although Roman thought and practice are closest to chronologically to contemporary forms of urban space, the influence of earlier civilizations interpreted through Rome was also significant. While the Etruscan planning practices, both religious and rational, were adopted by Rome partly as a means of defining a distinct Italian character to their cities in the peninsula and throughout the empire. Finally, the republican and imperial iconography of Rome was to find itself reinterpreted by later cities as the means by which to express independence, dominion and power.
The maximum population and size were determined before construction began because cities were built either where no city previously existed or where a small village stood. The planners then allotted adequate space for houses, shops, squares and temples. They decided how much water would be needed...