The armies had already lain hidden opposite each other for eight days when he gave this counsel. Mardonius perceived that the advice was good, and when night had fallen, he sent his horsemen to the outlet of the pass over Cithaeron which leads towards Plataea. This pass the Boeotians call the Three Heads, and the Athenians the Oak's Heads. The horsemen who were sent out did not go in vain, for they caught both five hundred beasts of burden which were going into the low country, bringing provisions from the Peloponnese for the army, and men who came with the wagons. When they had taken this quarry, the Persians killed without mercy, sparing neither man nor beast. When they had their fill of slaughter, they encircled the rest and drove them to Mardonius and his camp.