Answer
Sparta, the renowned military power of the Peloponnese, emerged as Pyrrhus' primary adversary during his campaign in the region. Pyrrhus, King of Epirus, sought to establish his dominance over the Peloponnese, but Sparta's formidable army, led by King Areus I, proved to be a formidable obstacle. The Spartans fiercely resisted Pyrrhus' advances, engaging in a series of battles that ultimately culminated in Pyrrhus' defeat and withdrawal from the Peloponnese.