In the spring of 440 Perikles was faced with a major crisis that imperilled the continuation of Athens' maritime empire. Her ally Samos, a commercially important island power which lay strategically off the coast of Asia Minor, rebelled. Perikles reacted decisively (as with Euboia six years previously) and even, his critics said, ruthlessly; although it took two campaigning seasons, the revolt was ultimately quelled. Samos had been a charter member of the Delian Confederacy and, as we saw in Chapter 1, took the lead both in initiating defection by the Ionians from the Persian force during the battle of Mykale (Herodotos 9.103) and in sowing the seeds of a new alliance with their mainland patrons, the Athenians (9.92 and 106). Samos played an important role in the allied double victory over the Persians at the Eurymedon river, where the Samian commander, a certain Maiandrios, captured eight enemy ships and had a commemorative statue of himself set up in the Samian Heraion. 1 As a major naval power Samos would have contributed significantly to allied operations in Egypt2 as well as during the 'First Peloponnesian War'. Plutarch says (Arist. 25.3) it was the Samians who proposed that the allied treasury be moved from Delos to Athens, and even if this is unhistorical it attests to Samos' prominence within the Confederacy.