An Oligarchy was described by Aristotle as the "rule of the rich" (although the word "plutocracy" would have been more accurate here). In an Oligarchy, the wealthy ruled the rest of society by force; those individuals needed not be related as they were unified with similar goals. The most typical examples for Oligarchic governments were some city-states of the ancient Greece and the Cartage, but many Renaissance city-states of Italy (like Venice or Florence) and even the pre-WWII Japan also seem to fall under this category.