Battle of Mantinea: The Thebans, led by Epaminondas, defeated the Spartans.

The Battle of Mantinea was fought on 4 July 362 BC between the Thebans, led by Epaminondas and supported by the Arcadians, Argives, Messenians, Thessalians, Euboeans and the Boeotian league against the Spartans, led by King Agesilaus II and supported by the Eleans, Athenians, and Mantineans. The battle was to determine which of the two alliances would dominate Greece. However, the death of Epaminondas and his intended successors would cost Thebes the military leadership and initiative to maintain Theban supremacy in the region. Similarly, the Spartans were weakened by yet another defeat and loss of troops. Epaminondas' death coupled with the impact on the Spartans of yet another defeat weakened both alliances, and paved the way for Macedonian conquest led by Philip II of Macedon.

Thebes is a city in Boeotia, Central Greece, and is one of the oldest continuously inhabited cities in the world. It is the largest city in Boeotia and a major center for the area along with Livadeia and Tanagra.

Epaminondas was a Greek general and statesman of the 4th century BC who transformed the Ancient Greek city-state of Thebes, leading it out of Spartan subjugation into a pre-eminent position in Greek politics called the Theban Hegemony. In the process, he broke Spartan military power with his victory at Leuctra and liberated the Messenian helots, a group of Peloponnesian Greeks who had been enslaved under Spartan rule for some 230 years following their defeat in the Third Messenian War ending in 600 BC. Epaminondas reshaped the political map of Greece, fragmented old alliances, created new ones, and supervised the construction of entire cities. He was also militarily influential and invented and implemented several important battlefield tactics.

Sparta was a prominent city-state in Laconia in ancient Greece. In antiquity, the city-state was known as Lacedaemon, while the name Sparta referred to its main settlement in the valley of Evrotas river in Laconia, in southeastern Peloponnese. Around 650 BC, it rose to become the dominant military land-power in ancient Greece.