History of the Peloponnesian War

Thucydides

Thucydides. History of the Peloponnesian War. Crawley, Richard, translator. London and Toronto: J. M. Dent and Sons Ltd.; New York: E. P. Dutton and Co., 1914.

And this was due not so much to scarcity of men as of money. Difficulty of subsistence made the invaders reduce the numbers of the army to a point at which it might live on the country during the prosecution of the war. Even after the victory they obtained on their arrival— and a victory there must have been, or the fortifications of the naval camp could never have been built— there is no indication of their whole force having been employed; on the contrary, they seem to have turned to cultivation of the Chersonese and to piracy from want of supplies. This was what really enabled the Trojans to keep the field for ten years against them; the dispersion of the enemy making them always a match for the detachment left behind.

If they had brought plenty of supplies with them, and had persevered in the war without scattering for piracy and agriculture, they would have easily defeated the Trojans in the field; since they could hold their own against them with the division on service. In short, if they had stuck to the siege, the capture of Troy would have cost them less time and less trouble.