Whatever the truth of these speculations there is no doubt that the Greeks of the end of the sixth century were fully alive to the political possibilities of the Thracian mines. Just after the Persian conquest of Thrace and Paionia Histiaeus of Miletus, one of the Persian king’s Greek vassals, almost succeeded in securing from the Great King possession of Myrcinus, a mining centre in the very district from which Peisistratus had got so much of his wealth[318]. He was in fact granted the gift by Darius, who however was persuaded by the far-sighted Megabazus to recall it. What alarms the Persian statesman is the prospect of an able Greek like Histiaeus establishing himself in a place where there are silver mines and forests suitable for ship-timber and a large mixed population. He prophecies that this population will quickly become the employees of the new owner and do his bidding day and night[319]. The Myrcinus incident is bound up in the narrative of Herodotus with the story of Pigres and Mantyes and their efforts to become tyrants of the Paionians[320]. Herodotus says definitely that Histiaeus did not aim at establishing a tyranny at Myrcinus[321]. But this statement seems to be simply an inference from the fact that Histiaeus was already tyrant of his own city of Miletus. Even if it is correct, the protests of Megabazus and their effect on Darius, who at once removed Histiaeus to a sort of honourable captivity in Persia, sufficiently show that according to Herodotus himself Myrcinus would have made Histiaeus in the eyes of Darius and Megabazus a different and altogether more dangerous sort of ruler[322]. It was still comparatively recently that Peisistratus had “rooted” his power at Athens partly on revenues from the river Strymon. When Histiaeus’ activities near that river so greatly alarmed the Persians, it is hard to believe that they were not thinking largely of the Peisistratids. Thus we have a confirmation of the view that the Peisistratids’ Thracian revenues had been derived from the silver mines, and the large mixed population that worked them. [Sidenote: Labour and commerce under the tyranny.]