The Dorian League was an ancient Greek alliance formed by the Dorian city-states, primarily in the 5th century BCE. It was established to promote mutual defense and cooperation among its members, which included cities like Sparta and Corinth. The league played a significant role in the political landscape of ancient Greece, especially during conflicts such as the Peloponnesian War. The Dorian League was characterized by its military and economic collaboration, allowing member states to pool resources and support each other in times of war. This alliance was distinct from the more famous Delian League, which was led by Athens and comprised primarily Ionian city-states. The Dorian League's influence waned as political dynamics shifted in ancient Greece.