Which region did Sparta conquer in the Messenian Wars?

Sparta conquered Messenia in the Messenian Wars.

Messenia lay west of the Eurotas valley, across the Taygetus range. Spartan tradition describes a First Messenian War in the late eighth century BCE and a later revolt known as the Second Messenian War, although the chronology and details remain debated by modern historians.

The conquest gave Sparta extensive farmland and a much larger dependent labor force. Many Messenians were reduced to the status of helots, whose agricultural work supported Spartan citizens and helped sustain the state’s military system.

Messenian resistance never disappeared completely. In the fourth century BCE, Theban campaigns led by Epaminondas freed Messenia and founded the city of Messene, permanently weakening Sparta.