History of the Peloponnesian War

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 wood-work 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.

Discovering this the Peloponnesians twisted up clay in wattles of reed and threw it into the breach formed in the mound, in order to give it consistency and prevent its being carried away like the soil.