It is perhaps surprising that it was only in 428 that a revolt within the Athenian empire gave Sparta the opportunity to implement its basic war aim of liberating Greece. This was the revolt of Mytilene on the island of Lesbos, to which Athens reacted with a prompt blockade. It was a shrewd Spartan move to summon the Mytileneans and other injured Greeks to the Olympic Games at this point, thus emphasizing that one aspect of the war was the tension between Dorians and Ionians. (Athens was hardly formally excluded from the solemnities, but Olympia always had a Dorian flavour.) Alcidas, the Spartan commander sent to assist the Mytileneans, failed, however, to do anything for them. On its surrender (427) the city narrowly escaped the wholesale executions and enslavements Cleon had recommended, but only as a result of second thoughts on the part of the Assembly (those events and decisions form the context of the famous “Mytilene debate”). It is to the Athenians’ credit that some of them were moved by the thought that their original decision was bloodthirsty.

There were no such doubters among the Spartans who supervised the final phase of Plataean 5th-century history. When the remaining Plataeans surrendered (some had already broken out to Athens), they were put to death to a man, after the “brief question” had been put to them, “Have you done anything for Sparta during the war?” It was a question that the Plataeans, despite some moving pleas, could answer only negatively. At least Cleomenes I in the 6th century and Agesilaus II in the 4th, both of whom applied much the same criterion as this in international affairs, made no pretense of being liberators of Greece. It is impossible for the modern reader to reflect on those two fully reported incidents at Mytilene and Plataea without coming to some general conclusions about Spartan behaviour; and Thucydides too was prompted to generalize in this fashion. His thoughts are attached to an account of civil strife at Corcyra, in the west, in 427. After a bloodbath, the democratic pro-Athenian faction prevailed over the oligarchical pro-Spartan party, with the Athenian commander Eurymedon making no attempt to stop it.

Speculation and unease

About this time the Athenians speculatively pursued their western interests, sending at first an expedition of 20 ships under Laches and Charoeades (c. 427) and then 40 more under Sophocles (not the tragedian), Pythodorus, and Eurymedon (426–425). This was a large force in total, given Athens’s other commitments, but its goals are difficult to assess; both radical and conservative motives are given, such as the desire to give the sailors practice (not a ridiculous motive, but an inadequate one), to cut off grain shipments to the Peloponnese (by which Corinth is presumably meant), or even to see if the whole island of Sicily could be brought under control, whatever exactly that might entail. (In 424, after mostly halfhearted warfare, the Sicilians put aside their internal differences at a conference in Gela, of which the Pan-Sicilian Hermocrates was the hero. The Athenian commanders returned home to an undeserved disgrace: their mandate for outright conquest had hardly been clear, nor were their resources sufficient.) The attempt by the Athenian general Nicias to take Megara by military means (427) had more immediate promise of success.

It is possible that even the Spartans were uneasy at what the main events of 427, at Mytilene and Plataea, had done for their image: they had been ineffective and brutal. Perhaps in partial redress, but also in pursuit of a traditional line of policy, they issued a general invitation to participate in a large (10,000 strong) colony at Heraclea in Trachis at the southern approach to Thessaly. This colonizing effort had intelligible short-term military motives, namely, a felt need to gain a hold on the Thracian region—the only part of the Athenian empire reachable by land—and a desire to deny Athens access to its larder on Euboea. But Thessaly had always featured and was always to feature in ambitious Spartan thinking; and Sparta may already have planned to make use of the amphictyonic vote that one certainly finds Heraclea exercising in the 4th century. That is, the Spartans were seeking to improve the unsatisfactory state of affairs which had led, as noted, to their initial intervention in the First Peloponnesian War—namely, their inability to exert influence in the Delphic amphictyony except indirectly through their metropolis, Doris.

From the propaganda point of view, the exclusion of Ionians, Achaeans, and some others was telling. Sparta was presenting itself as a leader of Dorians, not just as a selfish promoter of Spartan interests. This was the redress offered to a Greek world well-disposed toward Sparta at the beginning of the war but now perhaps dismayed by the way things were going. It was a pity that the brutality and violence of Spartan governors at Heraclea helped to ruin the project.

Athens’s magnificent refounding, also in 426, of the Ionian festival of Apollo on the island of Delos, where the Delian League had been established in 478 bce (see above The Delian League), must surely in part be seen as a response to Dorian Heraclea. (There were other motives too, such as desire for expiation for the plague, which had ravaged Athens a second time in the winter of 427–426.) Of the two great Panhellenic sanctuaries, Olympia had taken an ugly anti-Athenian look in 428, while the oracle of Delphi had actually approved the Heraclea colony. Athens, through Delos, was creating or inflating religious propaganda possibilities of its own. The same is true of an Athenian invitation to the Greeks at large, also (possibly) in the 420s, to bring offerings of firstfruits to Eleusis.

Land operations in the northwest occupied much of the purely military history of 426. They were conducted by one of the finest generals of the Peloponnesian War, the Athenian Demosthenes (no relation of Philip’s 4th-century opponent). He was at first spectacularly unsuccessful in some ambitious campaigning, perhaps not sanctioned by the Assembly at all, in Aetolia, where his hoplites were nearly helpless against the light-armed tactics of the locals. He was, however, able to retrieve the position subsequently, in Amphilochia, in circumstances that brought further discredit on Sparta, whose commander deserted his Ambracian allies.

Spartan calls for peace

The decisive year in the Archidamian War was, on Thucydides’ perhaps over-schematic account, 425. Demosthenes, whose credit with the Assembly must now have been excellent, obtained permission to use a fleet round the Peloponnese. He and his troops used it to occupy the remote Messenian headland of Pylos, a prominence at the north end of the Bay of Navarino, and to fortify it. The Spartans foolishly reacted by landing a hoplite force on Sphacteria, the long island to the south of Pylos. This force of 420 men, about half of them full Spartan citizens, was cut off by the Athenians, who thus acquired a potentially valuable bargaining chip. The Spartans sued for peace without reference to their allies (so much for liberation), but Cleon persuaded Athens to turn the offer down. Cleon made steep demands, including (in effect) the cession of Megara, showing that he—like Nicias in 427 and Demosthenes and Hippocrates in 424—grasped the strategic importance of Megara, even if the historian Thucydides did not.

One development that Thucydides does not report in its place, saving it for later mention, is the recall from exile in 427 or 426 of the Spartan king Pleistoanax, who is known to have favoured peace. Similarly, he notes only just before the Peace of Nicias of 421 that one Spartan worry was the imminent expiry in that year of their 30-year truce with the Argives; they did not want a war against Argos as well as Athens. That factor must in reality have been operative on Spartan minds for some years before 421. Like the return of Pleistoanax, this means that the capture of the Spartans at Pylos was by no means the only consideration making peace desirable at Sparta. Thus, 425 was less decisive than Thucydides sometimes suggests, perhaps because he was preoccupied with the activities of the Athenian Cleon.

Cleon’s influence

Thucydides disliked Cleon, as did another highly articulate contemporary, the playwright Aristophanes (who showed his hand especially in his comedy Knights, of 424). The picture that emerges from their works of Cleon and figures like him as “new politicians,” arising not from among the old or property-holding families but from the people, is largely a literary fiction. It was foisted on posterity by these ancient writers, who exaggerated the contrast between Pericles and his successors because they admired Pericles’ style. In social background, political methods, and particular policies the difference was not great. The real change in Athenian politics came only with the loss of the empire in 404 and the resulting partial breakdown in the “consensus politics” that had prevailed hitherto (because all social classes stood equally to gain from the empire, which financed political pay, provided land for all, and cushioned the rich against the cost of furnishing the fleet).

There are two lines of policy one can safely associate with Cleon from evidence other than that of Thucydides. One is an apparently large theoretical increase in the level of allied tribute (425–424) documented by an inscription. But it is not certain that the increase was sudden (details of the immediately preceding reassessments do not survive) or that it was ever turned into actually collected tribute. The other line of policy is an attempt, attested by Aristophanes, to draw Argos into the war in some way (its peace with Sparta, as mentioned, was due to expire in 421, the year in which, unknown to Cleon in 425, the Archidamian War was to end).

By declining the diplomatic solution, Cleon found himself committed to a military one. He succeeded dramatically, capturing 120 full Spartans and taking them back to Athens. This operation, achieved partly with the use of light-armed troops, ensured that there would be no invasion of Attica in 424. Athens was free to establish a base on the island of Cythera south of Laconia and make a serious and initially successful attempt on Megara.

Spartan recovery

At this point the balance of the war began to tilt again in Sparta’s favour: Brasidas arrived, on his way to the north, and saved Megara by a whisker. Moreover, an ultra-ambitious Athenian attempt to reinstate the mid-century position by annexing Boeotia failed at Delium; this was a major defeat of Athens by a Boeotian army whose key component was Theban. Meanwhile, Brasidas had reached the north, where he had won over Acanthus by a blend of cajolement and threats and where, too quick for Thucydides (the historian) to stop him, he had taken Amphipolis. From there he proceeded to capture Torone. All this adventurous activity looks at first sight uncharacteristically Spartan, but Thucydides’ picture of Brasidas as a romantic loner at odds with the regime back home is somewhat overdone, and there is reason to think that his liberation policies represented official Spartan wishes.

An armistice between Athens and Sparta in 423 did not stop further northern places from falling into Brasidas’s arms—almost literally: at Scione the inhabitants came out to greet him with garlands and generally received him “as though he had been an athlete” (a rare Thucydidean glimpse of a world other than war and politics). He briefly won over Mende as well, but Athens recovered it soon after; Cleon arrived in 422 and won back Torone too. The deaths of both Cleon and Brasidas in a battle for possession of Amphipolis removed two main obstacles to the peace that most Spartans had been wanting for several years—in fact, since Sphacteria or even earlier (the return of Pleistoanax). As noted, the imminent expiry of the Argive peace was another factor, as was the occupation of Cythera, which provided a base for deserting helots (it is surprising that Athens did not make more use of the Spartan fear of their helots, a far from secret weapon of war). The essence of the Peace of Nicias (421) was a return to the prewar situation: most wartime gains were to be returned. Sparta had resoundingly failed to destroy the Athenian empire, and in this sense Athens, whatever its financial and human losses, had won the war.

The Peace of Nicias was seen by Thucydides as an uneasy intermission between two phases of a single war. Corinth and Boeotia rejected the peace from the outset, and an energetic young Athenian politician, Alcibiades, tried to return to what may have been Themistocles’ policy of stirring up trouble for Sparta inside the Peloponnese. Alcibiades’ plans, like those of Themistocles, centred on Argos, once again a factor in Greek international politics after 421 and ambitious to revive mythical Dorian glories. This was a period of low prestige and unhappiness for the Spartans, who were actually excluded from the Olympic Games of 420 by their enemies, the people of Elis; they waited 20 years before extracting revenge for this and other insults (but contrary to most modern views, the Olympic ban almost certainly did not last for the whole intervening two-decade period).

An alliance of Athens, Argos, Elis, and Mantinea fought Sparta in 418 in the territory of Mantinea. Sparta, resolute in war as it was irresolute in politics, scored a crushing victory over its enemies. The shame of the Sphacteria surrender was wiped out in one day, and the Greek world was reminded of Spartan hoplite supremacy. If Athens, whose finances were now strong again, wanted outlets for its aggression, it would have to find them elsewhere than in the Peloponnese. It sought it first in Anatolia, second on Melos, and third in Sicily.