History of the Peloponnesian War

They spent this winter in sending round to their allies for iron, and in getting ready the other implements for building their fort; and meanwhile began raising at home, and also by forced requisitions in the rest of Peloponnese, a force to be sent out in the merchantmen to their allies in Sicily. Winter thus ended, and with it the eighteenth year of this war of which Thucydides is the historian.

In the first days of the spring following, at an earlier period than usual, the Lacedaemonians and their allies invaded Attica, under the command of Agis, son of Archidamus, king of the Lacedaemonians. They began by devastating the parts bordering upon the plain, and next proceeded to fortify Decelea, dividing the work among the different cities.

Decelea is about thirteen or fourteen miles from the city of Athens, and the same distance or not much further from Boeotia; and the fort was meant to annoy the plain and the richest parts of the country, being in sight of Athens.