History of the Peloponnesian War

And the men on the sea-coast, now making greater acquisition of wealth, led a more settled life: and some of them even surrounded themselves with walls, on the strength of growing richer than they had before been. For through desire of gain, the lower orders submitted to be slaves to their betters; and the more powerful, having a superabundance of money, brought the smaller cities into subjection.

And being now more in this state of things, some time after they made the expedition against Troy.

And Agamemnon appears to me to have assembled the armament because he surpassed the men of that day in power, and not so much because he took the suitors of Helen bound by their oaths to Tyndarus.