History of the Peloponnesian War

But the Lacedaemonians were heartened thereunto principally because they thought the Athenians having in hand a double war, one against them and another against the Sicilians, would be the easier pulled down, and because they conceived the breach of the last peace was in themselves. For in the former war, the injury proceeded from their own side, in that the Thebans had entered Plataea in time of peace; and because also, whereas it was inserted in the former articles that arms should not be carried against such as would stand to trial of judgment, they had refused such trial when the Athenians offered it. And they thought all their misfortunes had deservedly befallen them for that cause, remembering amongst others, the calamity at Pylus.

But when the Athenians with a fleet of thirty sail had spoiled part of the territory of Epidaurus and of Prasiae and other places, and their soldiers that lay in garrison in Pylus had taken booty in the country about, and seeing that as often as there arose any controversy touching any doubtful point of the articles, the Lacedaemonians offering trial by judgment, they refused it, then indeed, the Lacedaemonians, conceiving the Athenians to be in the same fault that themselves had been in before, betook themselves earnestly to the war.

And this winter, they sent about unto their confederates to make ready iron, and all instruments of fortification. And for the aid they were to transport in ships to the Sicilians, they both made provision amongst themselves and compelled the rest of Peloponnesus to do the like. So ended this winter, and the eighteenth year of the war written by Thucydides.

The next spring, in the very beginning, earlier than ever before, the Lacedaemonians and their confederates entered with their army into Attica, under the command of Agis, the son of Archidamus, their king. And first they wasted the champagne country, and then went in hand with the wall at Deceleia, dividing the work amongst the army, according to their cities.

This Deceleia is from the city of Athens at the most but one hundred and twenty furlongs, and about as much or a little more from Boeotia. This fort they made in the plain, and in the most opportune place that could be to annoy the Athenians, and in sight of the city.