"Ought I not to begin by describing how the change from timocracy to oligarchy arises?

Yes.

Well, I said, no eyes are required in order to see how the one passes into the other.

How?

The accumulation of gold in the treasury of private individuals is the ruin of timocracy; they invent illegal modes of expenditure; for what do they or their wives care about the law?

Yes, indeed.

And then one, seeing another grow rich, seeks to rival him, and thus the great mass of the citizens become lovers of money.

Likely enough.

And so they grow richer and richer, and the more they think of making a fortune the less they think of virtue; for when riches and virtue are placed together in the scales of the balance the one always rises as the other falls.

True.

And in proportion as riches and rich men are honored in the State, virtue and the virtuous are dishonored.

Clearly.

And what is honored is cultivated, and that which has no honor is neglected.

That is obvious.

And so at last, instead of loving contention and glory, men become lovers of trade and money; they honor and look up to the rich man, and make a ruler of him, and dishonor the poor man.

They do so.

They next proceed to make a law which fixes a sum of money as the qualification of citizenship; the sum is higher in one place and lower in another, as the oligarchy is more or less exclusive; and they allow no one whose property falls below the amount fixed to have any share in the government. These changes in the constitution they effect by force of arms, if intimidation has not already done their work.

Very true.

And this, speaking generally, is the way in which oligarchy is established...

The inevitable division: such a State is not one, but two States, the one of poor, the other of rich men; and they are living on the same spot and always conspiring against one another.

That, surely, is at least as bad.

Another discreditable feature is, that, for a like reason, they are incapable of carrying on any war. Either they arm the multitude, and then they are more afraid of them than of the enemy; or, if they do not call them out in the hour of battle, they are oligarchs indeed, few to fight as they are few to rule. And at the same time their fondness for money makes them unwilling to pay taxes."

--- Plato, The Republic