The Spartan Alliance is a strategic partnership formed between various city-states in ancient Greece, primarily aimed at mutual defense and military cooperation. This alliance was established in response to external threats, particularly from the Persian Empire, and was characterized by a strong military focus, with the city-state of Sparta often taking a leading role due to its renowned army. Members of the Spartan Alliance would collaborate in military campaigns and share resources to strengthen their collective security. The alliance played a significant role during the Peloponnesian War, where it opposed the Delian League, led by Athens. This rivalry shaped the political landscape of ancient Greece for many years.