The Theban Hegemony refers to a period in ancient Greek history during the 4th century BCE when the city-state of Thebes emerged as a dominant power in Greece. This era followed the decline of Sparta and was marked by Thebes' military successes, particularly at the Battle of Leuctra in 371 BCE, where they defeated the Spartans. Under the leadership of figures like Epaminondas, Thebes established a coalition of city-states known as the Boeotian League. This alliance allowed Thebes to exert influence over other regions, challenging the traditional dominance of Athens and Sparta in Greek politics and warfare.