sentences:  In addition, Mytilene was different from most allies because it was ruled by an oligarchy.Mytilene had contemplated ending its alliance with Athens, but Sparta had rejected her appeal for an alliance to enable this.However, this rejection had been prior to the outbreak of the Peloponnesian War, which created an opportunity for the Mytilenians, who sent an envoy to Olympia in 428 B.C.