The sole ruler of a state, who was usually differentiated from a "king" because the tyrant didn't go obtain his authority or power by means of a hereditary right.

Tyrants existed throughout Greek history, but some people refer to an "age of tyranny" (mid-seventh to late sixth centuries, B.C.) when most of the Greek city states (Sparta being the special exception) were ruled by tyrants.

The tyrannies, although passed on from a father to his son, rarely lasted longer than two generations.

In Asia Minor, the Persians installed tyrants to rule their Greek subjects, but such rulers were unpopular.