'A fundamental idea common to most poleis was that all male citizens had (at least theoretically) equal political rights based on ownership of property. In practice, whatever the political system adopted - tyranny, oligarchy or democracy - political power was dominated by a few aristocratic families who held for themselves all the important positions in the polis such as membership of elite councils, magistracies and the higher military ranks. Also, within these citizen bodies there were richer and poorer citizens. Overtime, and especially following the introduction of money, the richer class, whose status had once been based on land ownership, began to accumulate wealth from investments and loans they made, in effect increasing the difference between rich and poor. ' source
The Greek Polis or federation of them as an ideal society.