Age of Heroes
By the end of the 7th century BC, Sparta had become the most powerful state in the Peloponnese. Sparta acquired two powerful allies, Corinth and Elis, by ridding Corinth of tyranny, and helping Elis secure control of the Olympic Games. Sparta continued to aggressively use a combination of foreign policy and military intervention to gain other allies. Sparta defeated Tegea in a frontier war and offered them a permanent defensive alliance; this was the turning point for Spartan foreign policy. Many other states in the central and provincial northern Peloponnese joined the league, which eventually included all Peloponnesian states except Argos and Achaea.
The league was organized with Sparta as the hegemon, and was controlled by the council of allies which was composed of two bodies: the assembly of Spartiates and the Congress of Allies. Each allied state had one vote in the Congress, regardless of that state’s size or geopolitical power. No tribute was paid except in times of war, when one third of the military of a state could be requested. Only Sparta could call a Congress of the League. All alliances were made with Sparta only, so if they so wished, member states had to form separate alliances with each other. And although each state had one vote, League resolutions were not binding unless Sparta agreed with the majority vote.
The league provided protection and security to its members. It was a conservative alliance which supported Oligarchies in line with the values of Sparta and opposed tyrannies and direct democracies.