The Battle of Hemomenus was a battle of the Peloponnesian War which was fought in Phocis in 424 BC.
As Sparta pushed the Athenians back on all fronts, the Athenian demagogue Cleon's power and popularity were diminished. The Spartan general Leandros set out from Malis to invade Phocis, the Delian League's last mainland affiliate, with the objective of isolating Athens on mainland Greece. The Spartan army was joined by the mercenary Kassandra, while the Athenians hired the mercenary Medon the Snake-Haired to serve as their army's champion. In the ensuing battle, Kassandra slew 7 captains, 31 soldiers, and Medon, shifting the tide of battle in Sparta's favor. The Spartan victory at Hemomenus delivered Phocis to the Peloponnesian League's control, further weakening the Athenian cause.