Agesilaus II was king of Sparta from c. 400 to c. 360 BC. Generally considered the most important king in the history of Sparta, Agesilaus was the main actor during the period of Spartan hegemony that followed the Peloponnesian War. Although brave in combat, Agesilaus lacked the diplomatic skills to preserve Sparta's position, especially against the rising power of Thebes, which reduced Sparta to a secondary power after its victory at Leuctra in 371 BC.

The history of Sparta describes the history of the ancient Doric Greek city-state known as Sparta from its beginning in the legendary period to its incorporation into the Achaean League under the late Roman Republic, as Allied State, in 146 BC, a period of roughly 1000 years. Since the Dorians were not the first to settle the valley of the Eurotas River in the Peloponnesus of Greece, the preceding Mycenaean and Stone Age periods are described as well. Sparta went on to become a district of modern Greece. Brief mention is made of events in the post-classical periods.