Tell me, dear friend, how tyranny arises. That it is an outgrowth of democracy is fairly plain. Is it, then, in a sense, in the same way in which democracy arises out of oligarchy that tyranny arises from democracy?

The good that they proposed to themselves and that was the cause of the establishment of oligarchy—it was wealth, was it not?”

The insatiate lust for wealth and the neglect of everything else for the sake of money-making was the cause of oligarchy's undoing.

- Plato’s Republic