Roman history falls naturally into two parts .The city of Rome became an independent republic in 509 b.c. and remained a republic until the old self-governing institutions were replaced by one-man rule after the Battle of Actium in 31 b.c. Thereafter Rome and the empire it had by now acquired were ruled by a single man, holding initially the title of princeps (first citizen), and later the title of imperator (emperor) or dominus (lord).  This one-man rule lasted from 31 b.c. to a.d. 476, when a barbarian chieftain deposed the last emperor -although, in fact, the emperors had lost their real power many decades before.  The era of one-man rule is often called the "Roman Empire," to be distinguished from the Roman Republic. But this distinction is somewhat misleading, since most of the empire was acquired during the period of the republic. The distinction between Republic and Empire is therefore a distinction between the different kinds of government, and the word empire in this connection should not be confused with our modern use of the term in the territorial sense.

Prior to the establishment of the Republic there had been kings in Rome, traditionally from the founding of Rome by Romulus in 753 b.c. The famous story of this founding should not, however, be taken too seriously, since it is certain that a city existed on the site of Rome long before 753. The Italians who inhabited the Italian peninsula probably descended into Italy at about the same time as the various barbarian peoples entered Greece, during the second millennium b.c. Even before these invasions there is evidence of prehistoric cultures in Italy. The native kings of Rome were certainly replaced toward the end of the seventh Century b.c. when an Etruscan named Tarquinius Priscus added Rome to his territories. The Etruscans were at that time in control f most of Italy north of Rome. By capturing Rome they reached their furthest point of expansion to the south, and Rome became one of their capitals.

The Etruscans appear to have come from Asia Minor about 900 b.c. They brought a distinctive culture of their own and bequeathed to the Romans such practices as divination by the observation of the flight of birds and of other natural phenomena; the Romans continued throughout the history of both the Republic and the Empire to rely much upon the information as to lucky and unlucky days given by the augurs. It was also the Etruscans who probably reunited the small villages around Rome into one great city. But the Etruscans were never popular in Rome, and the rule by Etruscan kings was such that the Romans detested the title of king forever afterward. Although the traditional sixth king of Rome, Servius Tullius, was regarded much more favorably by the later Romans, it is possible that even he was an Etruscan, or ruled with Etruscan consent. The Roman nobles rebelled against the seventh king of Rome, Tarquinius the Proud (Superbus), and Succeeded in setting up their own institutions after they had expelled him from the city. The famous story of the Rape of Lucrece (by a son of Tarquinius) concerns the incident which ted to the Etruscan expulsion.