Ancient Rome developed from a small prehistoric settlement on the Tiber River in Latium in central Italy into an empire that encompassed all of the Mediterranean world. The history of Rome can be divided into three major epochs: the kingship from the legendary foundation of Rome to 509 BC; the republic from 509 BC to 31 BC; and the empire, which survived until Rome finally fell to the German chieftain Odoacer in AD 476. The genius of the Romans lay in the military, in government administration, and in the law, and they valued crafty diplomacy as much as military discipline. The Romans conquered Greece, adopting Greek culture and transmitting it to the medieval world. Unlike the Greeks, they did not develop a philosophical theory of state and society. Instead, they were the practitioners of power and law, and Roman civil law, which reached its peak under the emperors, excelled in precision of formulation and logic of thought. However, it was a law of inequality and social prejudice which also became part of the Roman heritage. Roman political institutions remained relatively stable during the imperial centuries and then disintegrated rapidly as the empire collapsed. An examination of the history of that era should reveal both why the Roman Empire remained stable and also why that stability ceased.
In the third century the Roman world plunged into a prolonged and nearly fatal crisis, for reasons that were numerous. There were sharp divisions between the opulent notables in the cities and the poor peasants in the rural areas which created tensions. The wars that began under Marcus Aurelius continued, and increased taxation destroyed the prosperity of the empire. To meet rising military costs and to pay the bureaucracy, the emperors debased the coinage, resulting in a terrible inflation. The defenses of the empire on the Rhine and Danube collapsed under the attack of various Germanic and other tribes, and the eastern provin...