The Athenian Thucydides (c490-395BC) wrote this history of the Peloponnesian War between the Spartans and the Athenians, believing that it would be a greater war than any that had preceded it, and his version of events would serve as "a possession for all time".
The fragmentary nature of ancient Greece increased the frequency of conflict, but conversely limited the scale of warfare. Unable to maintain professional armies, the city-states relied on their own citizens to fight, reducing the potential duration of campaigns. The rise of Athens and Sparta as pre-eminent powers, however, led directly to the Peloponnesian War, which saw further development of the nature of warfare, strategy and tactics. Fought between leagues of cities dominated by Athens and Sparta, the increased manpower and financial resources increased the scale, and allowed the diversification of warfare. Set-piece battles during the Peloponnesian war proved indecisive and instead there was increased reliance on attritionary strategies, naval battle and blockades and sieges.

This book is essential reading for anyone interested the military history of the classical world.