Battle of Mantinea
Beginning in the 6th century BC and continuing through the 5th and early 4th centuries, Sparta dominated the Peloponnese, and compelled its neighbors to join its Peloponnesian League and fight in its wars. This dominance naturally aroused anger amongst these neighboring states, and Sparta's allies proved themselves willing to rise up against their overlord on several occasions. In 418 BC, Mantinea joined a league of Peloponnesian democratic states that briefly pursued an anti-Spartan policy before being defeated at the Battle of Mantinea (418 BC).