The Histories · 7.205

For as he had two brothers each older than himself, namely Cleomenes and Dorieos, he had been far removed from the thought of becoming king. Since however Cleomenes had died without male child, and Dorieos was then no longer alive, but he also had brought his life to an end in Sicily, thus the kingdom came to Leonidas, both because was of elder birth than Cleombrotos (for Cleombrotos was the youngest of the sons of Anaxandrides) and also because he had in marriage the daughter of Cleomenes. He then at this time went to Thermopylai, having chosen the three hundred who were appointed by law and men who chanced to have sons; and he took with him besides, before he arrived, those Thebans whom I mentioned when I reckoned them in the number of the troops, of whom the commander was Leontiades the son of Eurymachos: and for this reason Leonidas was anxious to take up these with him of all the…

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