History of the Peloponnesian War

For the former invasions, having been short, hindered them not from reaping the benefit of the earth for the rest of the time. But now, the enemy continually lying upon them, and sometimes with greater forces, sometimes of necessity with the ordinary garrison making incursions and fetching in booty, Agis, the king of Lacedaemon, being always there in person and diligently prosecuting the war, the Athenians were thereby very grievously afflicted.

For they were not only deprived of the fruit of the land, but also above twenty thousand of their slaves fled over to the enemy, whereof the greatest part were artificers; besides they lost all their sheep and oxen. And by the continual going out of the Athenian horsemen, making excursions to Deceleia and defending the country, their horses became partly lamed through incessant labour in rugged grounds and partly wounded by the enemy.

And their provision, which formerly they used to bring in from Euboea by Oropus the shortest way, through Deceleia by land, they were now forced to fetch in by sea at great cost about the promontory of Sunium. And whatsoever the city was wont to be served withal from without, it now wanted, and instead of a city was become as it were a fort.