Plutarch says that before this time the Athenians were in the habit of distributing the Laurium revenues among themselves, and that Themistocles had the courage to persuade them to give the habit up[239]. This agrees with Xenophon where he declares that “no one even attempts to say from what period people have tried to work them[240].” The mines of Lydia, Cyprus, and Spain all appear to have been developed in the seventh century B.C.[241]. The Siphnian mines were at full work about 525 B.C.[242]. Mining operations are depicted on several Corinthian clay tablets, that cannot be later than the early part of the sixth century[243]. One of them is here reproduced (fig. 5). Herodotus says nothing about the date of discovery of the Attic mines in his account of the proceedings of 484 B.C.[244]. It would not be like him to keep silence about an epoch-making discovery, or even a phenomenal “rush,” if any had occurred just at this time. Elsewhere he tells us that the Siphnians were already distributing among themselves the money from their mines about the year 525 B.C.[245]. Modern writers have been inclined to talk of the great “rush” of 484[246]. But against the silence of Herodotus they can set only the reference in the _Constitution of Athens_ to the “discovery” at Maronea, which has been discussed already. What made the great impression at this time was probably not so much the output as the employment of the output on the building of a fleet. That surely is the point of the contemporary allusion in the _Persae_ of Aeschylus. The chorus of Persian elders tells the Persian queen about the Athenians’ Fount of silver, treasure of the land[247] just after mentioning the prowess of the Athenian troops, and just before explaining the weapons that they use. The idea proposed in 484 by Themistocles was not original. Seven years earlier the Thasians had used the revenues from their mines to build a fleet against the Persians[248]. It was doubtless the success of the Athenian fleet in a supreme crisis that caused the Athenians to remember with such pride this triumph of the voluntary system. There can therefore be no question that the mines were worked in the sixth century[249]. But if we are to understand the position of the leader of the mining interests at that period, we must learn something about the conditions and position of the miners. [Sidenote: and the miners free men, good material for a political faction.] The leaders of the Plain and Coast had a powerful body of citizens behind their backs. The mines on the other hand, at least from the time of Xenophon, were worked almost exclusively by slaves[250].