The defeat of Xerxes’ Persia left a new situation on the Greek mainland after 479 BC. The Hellenic League, led by Sparta, still pursued war with the Persians, but the fighting now took place across the Aegean far from the shores of the Peloponnese. The threat to Sparta had been erased, and was now replaced with a military venture of uncertain strategic value for Lacedaemon – a fact which divided opinion back home. Nevertheless, under the leadership of Pausanias, nephew of Leonidas and the victor at Plataea, Sparta continued the campaign to free Ionia and the northern and eastern Greeks from the Persian yoke. Cyprus was liberated, and Byzantium too in 478 BC.
Athens, whose large fleet now made it the mightiest Greek naval power bar none, had willingly played second fiddle to Sparta during the Persian invasion. But the balance of power had shifted perceptibly between the two city-states. In the late sixth century, Sparta’s greater military strength had allowed the Agiad king, Cleosthenes, to march on Attica; however Athens of 478 BC had grown much stronger. At Plataea the year before it had nearly matched the Spartan contingent of 10,000 hoplites, and at Salamis in 480 BC, Athenian ships had done the brunt of the fighting. Now the Athenians were building a long wall to defend Athens and the port of Piraeus as a single entity, and had independently liberated the city of Sestos, a town on the Hellespont, through which shipments of grain from the Black Sea passed. Not only was Athens coming into its own as a major Greek power, it was also better suited than Sparta for naval campaigning in the Aegean Sea.
As head of the Hellenic League forces, Pausanias had antagonized the Athenian and other Greek naval officers in Byzantium with his harsh style of command. A headstrong man with clear tendencies to hubris, Pausanias may have entertained ambitions of greatness that his position as regent (for Leonidas heir Pleistarchus) did not allow him to fulfill. His position as commander of the Hellenic League was impressive, but like his regency it was a temporary honor, and he served at the behest of the ephors. Much like Lysander, nearly a century later, Pausanias may have schemed to usurp power. Allegedly, he released Persian prisoners of war who were relations of Xerxes, and then wrote to the Persian emperor, proferred his services, and suggested he marry the emperor’s sister to solidify the arrangement. When word reached Sparta that something was amiss, the ephors recalled him from Byzantium and placed him on trial for his conduct. He was acquitted, but relieved of his command. The Hellenic League allies had in the meantime selected the Athenians to command their combined forces. Pausanias returned to Byzantium a second time, as a private citizen ostensibly there to fight, but his behavior was once again suspect, and he was ejected from the city by the Athenians. When rumors of his consorting with the enemy reached Sparta once more, the ephors sent for him, and on his return, they secured incriminating evidence of his treachery. Moments before his arrest, Pausanias fled to a temple; the ephors bricked up the exits, and eventually removed him as he lay dying of starvation.
Not long thereafter, the Eurypontid king, Leotychidas was on campaign in Thessaly against pro-Persian Greeks when he was discovered to have taken a large bribe of silver. He was arrested, but managed to flee Sparta, and ended his life in Tegea years later. In the absence of both Pausanias and Leotychidas, Sparta was left without royal leadership for a span of years before Pleistarchus and Archidamus (son of Leotychidas) were able to step up. In the meantime, Athens under the leadership of Cimon successfully led the war against Persia in the north and east, liberating cities and islands, and gradually building an alliance system of its own. In either 469 BC or 466 BC, Cimon and the Delian league forces defeated a large Persian contingent in a combined sea/land battle at the Eurymedon river in Asia Minor. Athenian hegemony in the Aegean and Ionia was a reality.
The new Athenian-led alliance came to be known as the Delian League, as its treasury was kept on the island of Delos. Conducting naval warfare, and keeping triremes manned and at sea for extended periods, was immensely more expensive than land warfare and the Delian fleet was financed by the alliance members. It turned out that alliance members tended to pay the treasury rather than volunteer their men and ships, and so the alliance effectively was an Athenian-controlled navy funded in part by the other members. This skewed arrangement introduced a dynamic into the alliance that would gradually transform it into an Athenian empire in years to come, wherein alliance members were more captive to the alliance than voluntary members. Sparta of course had its own long-standing alliance – the Peloponnesian League, but it was structured as an alliance of mutual defence and had no significant standing expenses. By the 460’s therefore Greece had three major alliance systems: the overarching Hellenic League, the older Peloponnesian League led by Sparta, and the new Delian League led by Athens. Politics in Greece were becoming ever more complex.
Matters nearly came to a head between Sparta and Athens in 465 BC. Thasos was an island in northern Aegean and a member of the Delian League which had disagreements with Athens about control of precious metal mines and trade on the mainland. Relations broke down, and Thasos withdrew from the League. To enforce its will, Athens invaded, and defeated the Thasians in battle. The defenders retreated to their fortified city, and a two-year long sieged ensued. The desperate Thasians appealed secretly for Spartan intervention against Athens, hoping that an invasion of Attica would force Athens to withdraw its besieging forces from Thasos. According to Thucydides, the Spartans not only debated the proposal, but even decided for it. Scholars take this as an indication that apprehensions of Athenian power were already so well-established in Sparta that it was willing to break its alliance with Athens and go to war over a matter which hardly concerned it. In the event, the earthquake in Laconia of 464 BC and the ensuing helot revolt made an invasion of Attica out of the question. On the contrary, the Spartans were so hard pressed by the dual calamities that they sought aid from their allies, including Athens, which, one must surmise, had not learned of the Spartan plan. Left to its fate, Thasos succumbed to the siege in 463 BC. It had to surrender its fleet, tear down its walls, and become a tributary to the early Athenian empire.
- Kagan, Donald. The Peloponnesian War.
- Thucydides. The History of the Peloponnesian War.
- Rusch, Scott. Sparta at War: Strategy, Tactics and Campaigns.
- Cartledge, Paul. The Spartans.