Peloponnesian League
The Peloponnesian War (431–404 BC), was fought between the Athenian dominated Delian League and the Spartan dominated Peloponnesian League. The increased manpower and financial resources increased the scale, and allowed the diversification of warfare. Set-piece battles during this war proved indecisive and instead there was increased reliance on naval warfare, and strategies of attrition such as blockades and sieges. These changes greatly increased the number of casualties and the disruption of Greek society.