What was the alliance formed by nearly all the poleis in the Peloponnesus to maintain order?

The Peloponnesian League was an alliance formed primarily by city-states in the Peloponnesus during the classical period of ancient Greece, primarily to maintain order and mutual defense against external threats, particularly from the powerful Athenian Empire. The league was dominated by Sparta, which held significant military strength and influence, directing the policy and actions of its members.

The goal of the Peloponnesian League was to provide a unified front against aggressors and ensure stability within its member states. This collective military and political alliance helped to counterbalance the influence and power of the Delian League, which was led by Athens. Understanding the context of these alliances is crucial, as the rivalry between the Peloponnesian League and the Delian League ultimately sparked the Peloponnesian War, a significant conflict that shaped the course of Greek history.

The other choices represent different alliances or leagues that played distinct roles in ancient Greek history, but they do not pertain to the organization of city-states in the Peloponnesus aimed specifically at maintaining order among themselves.