History of the Peloponnesian War

For before this summer the enemy's invasions, being of short duration, did not prevent the Athenians from making full use of the land during the rest of the year; but at this time, the occupation being continuous, the enemy sometimes invading the country with a larger force and at others the regular garrison overrunning the country, as it was compelled to do, and carrying off booty, while Agis, the king of the Lacedaemonians, who was present in person, carried on the war in no desultory fashion, the Athenians were suffering great damage.

For they were deprived of their whole territory, more than twenty thousand slaves had already deserted, a large proportion of these being artisans, and all their small cattle and beasts of burden were lost; and now that the cavalry were sallying forth every day, making demonstrations against Deceleia and keeping guard throughout the country, some horses were constantly going lame because of the rocky ground and the incessant hardships they had to endure, and some were continually being wounded.

There was this further disadvantage: the bringing in of provisions from Euboea, which had formerly been managed more expeditiously by way of Oropus overland through Deceleia, now became expensive, the route being by sea round Sunium. Everything alike which the city needed had to be imported, and Athens ceased to be a city and became a garrisoned fortress.