The Histories · 9.14

Mardonios then was retiring out of the way, and when he was already upon a road a message came to him saying that another body of troops in advance of the rest had come to Megara, consisting of a thousand Lacedemonians. Being thus informed he took counsel with himself, desiring if possible first to capture these. Therefore he turned back and proceeded to lead his army towards Megara, and the cavalry going in advance of the rest overran the Megaran land: this was the furthest land in Europe towards the sun-setting to which this Persian army came..

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