The Histories · 6.84

The Argives then say that this was the reason why Cleomenes went mad and had an evil end: but the Spartans themselves say that Cleomenes was not driven mad by any divine power, but that he had become a drinker of unmixed wine from having associated with Scythians, and that he went mad in consequence of this: for the nomad Scythians, they say, when Dareios had made invasion of their land, desired eagerly after this to take vengeance upon him; and they sent to Sparta and tried to make an alliance, and to arrange that while the Scythians themselves attempted an invasion of Media by the way of the river Phasis, the Spartans should set forth from Ephesos and go up inland, and then that they should meet in one place: and they say that Cleomenes when the Scythians had come for this purpose, associated with them largely, and that thus associating more than was fit, he learnt the practice of…

Herodotus of Halicarnassus · trans. G. C. Macaulay, 1890
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