Battle of Mantinea
The Battle of Mantinea in 418 B.C. was part of the Second Peloponnesian War between the Greek city states of Athens and Sparta and their allies. The Spartan King Agis invaded the allies of Athens Argos and Matinea. Athens sent a small force to assist, but the allied army was badly beaten by the Spartans. This, the largest land battle of the war, took place when the opposing forces were nominally at peace. Sparta had restored itself to unquestioned hegemony of the Peloponnesus.
The Battle of Mantinea in 362 B.C. fought as part of an effort by Sparta and Athens to stop the growing power of Thebes after their defeat of Sparta at the Battle of Leuctra in 371 B.C. Each army numbered about 25,000 men, with Epaminondas the great leader of Thebes once again overwhelming his enemies with a similar tactic that he used at Leuctra. Unfortunately, he was killed in the moment of victory.
Encyclopedia of Military History, Dupuy & Dupuy, 1979