 Mardonius created a fortified encampment on the north bank of the Asopus river in Boeotia covering the ground from Erythrae past Hysiae and up to the lands of Plataea.The Athenians sent 8,000 hoplites, led by Aristides, along with 600 Plataean exiles to join the Allied army.The army then marched in Boeotia across the passes of Mount Cithaeron, arriving near Plataea, and above the Persian position on the Asopus.