After this appeal to the gods Archidamus put his army in motion. First he enclosed the town with a palisade formed of the fruit-trees which they cut down, to prevent further egress from Plataea; next they threw up a mound against the city, hoping that the largeness of the force employed would ensure the speedy reduction of the place. They accordingly cut down timber from Cithaeron, and built it up on either side, laying it like lattice-work to serve as a wall to keep the mound from spreading abroad, and carried to it wood and stones and earth and whatever other material might help to complete it. They continued to work at the mound for seventy days and nights without intermission, being divided into relief parties to allow of some being employed in carrying while others took sleep and refreshment; the Lacedaemonian officer attached to each contingent keeping the men to the work. But the Plataeans, observing the progress of the mound, constructed a wall of wood and fixed it upon that part of the city wall against which the mound was being erected, and built up bricks inside it which they took from the neighbouring houses. The timbers served to bind the building together, and to prevent its becoming weak as it advanced in height; it had also a covering of skins and hides, which protected the woodwork against the attacks of burning missiles and allowed the men to work in safety. Thus the wall was raised to a great height, and the mound opposite made no less rapid progress. The Plataeans also thought of another expedient; they pulled out part of the wall upon which the mound abutted, and carried the earth into the city.