The history of ancient Rome spans a period of almost a thousand years. Over this period, the form of political organization went from a small, localized monarchy to a republic and then evolved into an empire that reached from Egypt to Britain and the Black Sea to the Atlantic Ocean.
According to Livy, Rome was founded by Romulus in approximately 753 BC. He was the first of the Seven Early Kings who were absolute rulers before the foundation of the Republic in 509 BC. Although it is difficult to separate myth from history for this period, it is likely that the earliest stages of Roman government did involve absolute kings.
The Republic lasted from 509 BC to 27 BC, when the Empire was established. During the Republican period two elected consuls were the most important officials. The Senate, a body composed of patricians, would advise the consuls, although the plebeians gained additional powers over the course of the Republic.
Once the Empire was established, one or more emperors would rule (at certain periods, there were two or more emperors, each in charge of a different geographical region).