After the death of Darius at the end of the Peloponnesian War, his eldest son Artaxerxes succeeded him to the throne, despite the plotting of Cyrus, he returns to Sardis, where he is under the watch of Tissaphernes who begins to assemble an army of Greek mercenaries. Following the end of the Peloponnesian War there are large numbers of unemployed Greek soldiers. The Spartan Clearchus, who had been Spartan governor in Byzantium until his attempt at tyranny there got him expelled, was recruiting for Cyrus and by 401 Cyrus has an army of 13,000 Greeks, including 10,600 hoplites, one of whom was Xenophon, along with 12,000 foot and 2,600 cavalry from the empire. In Spring, they begin to march toward Susa. Artaxerxes is rather slow in preparing for the enemy but eventually got together an army of 30,000 foot and 6,000 cavalry, Xenophon says 900,000, and met Cyrus' army in the summer of 401 at Cunaxa, on the Babylonian frontier. The Greeks were victorious overall, but part of their army had been defeated, and Cyrus was killed. Result is a large Greek army (10,000) stuck in the middle of a hostile Persian empire, with no one to fight for and worse still no one to pay them. The army refuses to surrender but take up Tissphernes' offer to escort them out of the country, believing Persians just wanted them out the way. Tissaphernes treacherously kills a number of the Greek officers, hoping to induce surrender , The Greeks refuse to surrender and Xenophon is elected general and exhorts army to continue their march despite no guides, no supplies, inexperienced commanders and hostile territory. They eventually reach the Euxine sea, and thence to the Greek city of Trapezus, rested for a month, plundered some neighbouring territory, consider founding a city in the region but soldiers want to go home, and cohesion breaks down so they make their way down the coast, to Byzantium and are transported across by a Spartan admiral at the request of Pharnabazus, who didn't want this Greek army on Asian soil any longer. They worked for the Thracians for a short time and then were hired by Sparta in a war against Persia. Expedition showed that a Greek army could carry arms in to Persia, and in some sense is a forerunner of Alexander the Great's conquest of the Empire later in the century.
Was Pausanius' opposition to the imperialism of Lysander based on the moral ground that absolute power was corrupting absolutely the Spartans who exercised it abroad or was it for more selfish reasons? Whatever the motive Pausanius was inconspicuous by his absence in this drive to empire in the period 404 to 395 and only after his exile in a tract did he speak out against it.
With Athens temporarily back in the fold it was now time to deal with those allies who had opposed Sparta's policy with regard to Athens. In 402 Elis is the first to feel the anger of Sparta, Agis to revenge himself for the personal humiliation he suffered at their hands and also to wipe out the political defeat suffered by Pausanius' acquittal. The Eleans had excluded Sparta from the Olympic games of 420 BC because of their fighting Argos and Mantinea. Later they refused to allow Spartan king Agis to sacrifice at Olympia, and so the Lacedaemonians demanded they pay tribute for the long war against Athens and that they allow their townships to be independent. When the Eleans refused, Agis marched an army against them; but he turned back when an earthquake was interpreted as a bad sign. However, the next year Agis, joined by cities who threw off their subjection to Elis, sacrificed, plundered Eleans territory, and left a Spartan harmost and garrison at Epitalion to support the oligarchs led by Xenias. Elis surrendered and joined the Peloponnesian league, though they were allowed to continue superintending the Olympic games. Corinth and Boeotia are again absent from this Peloponnesian campaign. Another piece of outstanding business was completed in 400 with the expulsion of the Messenian colony at Naupactus and Cephallania. In 400 Agis had died and had been succeeded by Agesilaus II, after Lysander put his influence behind him against Agis' son Latychidas. "But Diopeithes, a man very well versed in oracles, said in support of Leotychides that there was also an oracle of Apollo which bade the Lacedaemonians beware of the lame kingship. Lysander, however, made reply to him, on behalf of Agesilaus, that he did not suppose the god was bidding them beware lest a king of theirs should get a sprain and become lame, but rather lest one who was not of the royal stock should become king. For the kingship would be lame in very truth when it was not the descendants of Heracles who were at the head of the state.  After hearing such arguments from both claimants the state chose Agesilaus king". Xenophon, Hellenica III.3
Sparta also began asserting her authority in Northern Greece, reviving the colony of Heraclea, near Thermopylae and pushed into Thessaly. A harmost and garrison were placed in Pharsalus at the request of the Thessalian federation as a counter to Macedonian expansion. Struggling with internal conflicts and war with the Thracians, the Byzantines asked the Spartans for a general. Clearchus was sent and given supreme authority, which he used to put to death the chief magistrates and most prominent citizens, killing and exiling the wealthy in order to appropriate their property. He used the money to hire mercenaries and was unwilling to give up his power; so the Spartans sent an army against him. Clearchus took his forces to Selymbria, where they were defeated by the Spartans; but Clearchus fled to Cyrus in Ionia. Cyrus had been given authority by his brother Artaxerxes over all the Persian satrapies on the Aegean Sea; Cyrus gave funds to Clearchus to raise a mercenary army. Cyrus also financed mercenary forces of Aristippus and Menon in Thessaly and mercenaries led by the Boeotian Proxenus, the Arcadians Agias and Sophaenetus, and an Achaean named Socrates, ostensibly for the siege against Miletus or to fight against the warlike Pisidians.
During the revolt Cyrus encouraged the Greek cities of Asia Minor to revolt, to weaken Tissaphernes. After Cunaxa, Tissaphernes returned to Sardis with the intent of retaking the Greek cities and began by attacking Cyme. The Asiatic Greeks appealed to Sparta, as their only option for help. Sparta's relationship with Persia has changed, the Greek force under Cyrus had included, in addition to the mercenaries, a division of Neodamodeis. The success of the Ten Thousand had inspired Greeks generally and Sparta especially to think that the Persian empire was not as invulnerable as it had seemed 400. Sparta sent an army to Asia, supplemented by many of the Ten Thousand under command of Thibron, who is unable to maintain good discipline, and they doesn't accomplish very much Sparta's decision to covertly support Cyrus in his rebellion shows the hand of Lysander again. In 399 Dercyllidas replaces Thibron, and takes advantage of the tensions between Tissaphernes and Pharnabazus to make a truce with Tissaphernes. He concentrates on areas under Pharnabazus' control and is able to gain control of the Troad easily, because of the internal political situation there. He took booty to pay his mercenary troops and establishes Troad as a sort of forward post in Asia. He concludes truces with Pharnabazus and Tissaphernes while ambassadors went to Susa to negotiate with the king. In 398 he is active in the Chersonese. But in 397 Dercyllidas is ordered to Caria the Spartan ambassadors to Susa had been rebuffed as Pharnabazus had convinced the king to prosecute a war against Sparta by sea. Persia had a larger fleet available than Sparta, but needed a good commander. Conon on Cyprus since Aegospotami, and through various channels, manages to get command of a Persian fleet of 300 ships being prepared in Phoenicia and Caria. Conon doesn't wait for preparations to be completed but sails with 40 ships to Caunus in Caria. Sparta sends fleet of 120 ships from Rhodes to blockade him. Dercyllidas is en route by land A joint force of Tissaphernes and Pharnabazus break the blockade at Caunus, went to stop Dercyllidas in the valley of the Maeander. An armistice is concluded when both sides prefer not to start a battle. Conon meanwhile moves to Rhodes and is able to win it away from Sparta, an anti-Spartan democracy is instituted. The Spartans realize they have to conduct things more vigorously. King Agesilaus, who had taken the throne in 398, is sent out to replace Dercyllidas and in 396 brings a force of 2,000 Neodamodeis and 30 Spartans of the officer class, including Lysander. Lysander is extremely ambitious and portrays himself as a new Agamemnon going out to conquer the East. In the autumn of 398 Agesilaus invades Pharnabazus' territory but doesn't accomplish much of lasting value, on the other hand he takes considerable booty. Passing the winter training at Ephesus, he organized a force of well-trained cavalry. In the spring of 395 he has victories in Lydia against Tissaphernes who is replaced (and executed) by Tithraustes. Tithraustes offered peace to Agesilaus, on terms that Agesilaus is to leave the Asia Greek cities to enjoy autonomy, but pay tribute to Persia , 6-month armistice, with Tithraustes to consult with Sparta, while Agesilaus still kept busy operating against Pharnabazus. In the autumn of 395 Agesilaus is campaigning in Pharnabazus' satrapy again and ravages his territory up to the walls of his capital at Dascylion. Again an agreement is reached with Pharnabazus. Agesilaus prepares a fleet of 120 ships, under the command of the inexperienced Pisander, to deal with Conon and the Persian fleet. In the summer of 394 Conon and Pharnabazus move their fleet from Cilicia to the coast of the peninsula of Cnidos. Pisander, with much smaller fleet, sailed out to meet them. His Asian contingents deserted him and the rest of his ships were mostly taken or destroyed and Pisander himself was killed. They followed up this victory by expelling Spartan harmosts from the coastal cities of Asia Minor, Pharnabazus agreeing with the persuasive Conon in promising not to fortify their citadels but granting them autonomy. Thus the maritime power of Sparta was destroyed.
The Persian king, always anxious to stir up trouble among the Greeks, sent Timocrates of Rhodes with fifty talents of precious metal to encourage the anti-Spartan politicians in Thebes, Corinth and Argos. Xenophon seems to think this was the main cause of the war that followed. But if it was a factor it was certainly not the only one. Most city states seemed to have both a pro-Spartan and an anti-Spartan faction. In Athens, however, there was no oligarchy to favour the Spartan brand of politics. The Athenians took no gold, according to Xenophon, but were persuaded by the Thebans to join them. At both Thebes and Argos the picture was much more complicated. Meanwhile the Athenian admiral Conon, who had fled from the final battle at Aegospotami to Cyprus where he was received by Euagoras, by the advice of Pharnabazus was given command of a fleet of 300 Phoenician ships and took Rhodes away from the Spartans.
The foundations of the Spartan empire had now been seriously undermined.
The war started when Androcleides and Ismenias at Thebes calculated that if they could involve Boeotia in a war with Sparta, victory would be assured because of the financial backing of Persia and the animosity felt for Sparta at both Athens and Corinth. No direct appeal would prompt the Boeotians to war so they had to be more indirect.
They persuaded some Phocians to raid the territory of the Locrians, with whom they had a long standing boundary dispute. When the Locrians retaliated, the Phocians began a full fledged invasion. The Locrians appealed to Boeotia for help and Ismenias and his friends persuaded the Boeotians to support the Locrians. The Phocians then begged the Spartans to forbid the Boeotians to make war on them. The Spartans demanded that the Boeotians submit to arbitration. The Boeotians refused and continued their efforts to invade Phocis.
Sparta welcomed a chance to discipline the Boeotians because they were still angry that, in 403 BC, the Boeotians had refused to join Pausanias' invasion of Attica (a territory dominated by Athens) and had even persuaded the Corinthians to remain aloof as well. Sparta miscalculated badly. They seem to have forgotten about the latent hostility of Athens, Argos, and Corinth. They were so pleased over King Agesilaus' victories in Asia and were lulled by the unaccustomed calm in most of the rest of Greece.
There is a double invasion of Boeotia occurs. Sparta sent Lysander to muster the Phocians and their local allies and to persuade Orchomenus to secede from the Boeotian League, while King Pausanias collected further allies at Tegea.Firstly Pausanias advances from the south and Lysander comes down from Heraclea in the north. Thebes appeals to Athens for support and the Athenian Assembly makes a bold decision to break free of Spartan rule concluding 'eternal alliance' with Boeotia. Lysander wins over Orchomenos en route and heads to Haliartus (between Orchomenos and Thebes) to rendezvous with Pausanias. Lysander arrives first, attacking the town. The Haliartans from their walls see the approaching Theban army and are determined to resist the Spartans. They sally from their gates catching Lysander by surprise and attack on both flanks, the Spartan forces are driven back and Lysander is killed. Pausanias' army arrived soon afterward, followed by an Athenian contingent under Thrasybulus. Pausanias decides not to attempt a battle and asks for a truce to retrieve dead bodies of Lysander's and his soldiers The truce is granted on condition that the Peloponnesian army leave Boeotia. Pausanias for this action is condemned, spending the rest of his life in exile at Tegea. Result is a new League is formed to resist Sparta.
The growing Theban alliance captured the Spartan colony of Heraclea, killed all the Spartans there and exiled all other Peloponnesians they found in the area. An alarmed Sparta recalled Agesilaus from his efforts in freeing the Asian Greeks from Persian domination and in Sparta a levy was held and Aristodemus declared commander of an expeditionary force.
Thebes and Athens are now joined by Corinth and Argos, whose company is soon increased by the addition of Euboea, Acarnania, the Thracians of the Chalcidice, and others. The Thebans eject the Spartans from Heraclea and Thessaly, then the Phocis Maritime league to resist Sparta begins forming in the wake of the Spartan naval defeat at Cnidus. Included in this are Rhodes, Iasus, Cnidus, Ephesus, Samos, Byzantium, Cyzicus and Lampsacus.
In Spring 394 the allies gathered there forces at the Isthmus. Corinth wanted to march on Sparta directly but time was wasted in debate among the allies. Meanwhile, Sparta marched through Arcadia to Sicyon, from there to the Saronic gulf via Nemea where the two sides met.
In the wake of Haliartus in 395, Agesilaus recalled from Asia came back via the overland route, through Thrace and Macedonia reluctantly abandoning his successful series of campaigns against the Persians.
For the expedition to Asia, originally he and Lysander had taken an army of 30 Spartans of the office class, 2000 Neodamodeis, and 6000 allies. Xenophon clearly indicates that the whole force raised did not go back with him. Once Agesilaus was in Asia, he gathered troops from Ionia, Aeolis, and the Hellespont and recruited a mercenary cavalry force. In the early spring of 395 BC he had encouraged strict military training and top physical conditioning by placing the Spartiates in charge and offering prizes for excellence in physical conditioning, weapons use, and military drill. Among the troops recruited for his force were the veterans of Xenophon's 10,000 who had served as mercenaries for Cyrus and then had to fight their way out of Persia when Cyrus was killed. This well trained army was then seasoned by a series of successful campaigns against the Persians in 395 and early 394 BC.
Agesilaus felt that he needed both replacements and reinforcements. To make sure that he got the best troops, he offered prizes to the Asian Greek cities and mercenary captains that could produce the best equipped and trained forces. He purposely recruited archers, peltasts, and cavalry as well as hoplites. He also insisted that the cavalry be on the best mounts available. He offered gold and expensive armour as prizes.
Leaving a garrison of 4,000 at Euxenus with a promise that he would return, he followed the old invasion route taken by Xerxes' Persians almost a hundred years before. As his army crossed through Thessaly, the Thessalians, who had joined the Theban alliance, sent a cavalry force to harass and slow down his march. To protect his foot soldiers from the enemy cavalry, Agesilaus used tactics like those of Xenophon during the march of the 10,000. He formed his foot into a hollow square with the baggage in the centre.
Unlike the 10,000, Agesilaus also had a large cavalry force. He used this force to catch the Thessalian cavalry by surprise. Xenophon, in Book 4, chapter 3, paragraph 9 of his Hellenica, says that Agesilaus was "particularly pleased that a cavalry force he had chosen defeated the people who, more than any others, pride themselves on their horsemanship."
In Boeotia, he joined forces with a Spartan Mora (approximately 600 men) that had come from watching Corinth, a half Mora that had been helping to protect Orchomenos (the only Boeotian city to side with Sparta and Phocis in this war), and a force of Orchomenian and Phocian Hoplites. They found the enemy gathered in the plain of Coronea, near the base of mount Helicon and a small river that runs North-eastward to eventually flow into Lake Copais.
Agesilaus unable to follow up his victory, left Boeotia by crossing Corinthian Gulf , the Isthmus being garrisoned by Confederates.
Although Sparta had achieved two decisive victories in the field overturning the debacle at Haliartus and Agesilaus had got his Asian booty back home, the strategic picture did not look so good. Orchemenos and Phocis had been secured but central Greece had not been recovered, the confederation still held together and things were to get worse. The polemarch Gylis who had probably commanded the mora that had joined Agesilaus at Coronea was killed in Locris making bad use of his peltasts on his march home.
In 393 Conon captured and garrisoned the island of Cythera lying off the easternmost prong of the Peloponnese. From here he could make raids on Laconia and Messenia bringing back bad memories of the Athenian capture of Pylos during the Athenian war. He also persuaded Pharnabazus to make more substantial contributions to the anti-Spartan war effort. The money was used to complete the rebuild of Athens' fortifications destroyed in 404 and to finance a force of mercenary peltasts to be stationed permanently near the isthmus under Iphicrates.
The Lacedaemonians had no difficulty in the choice of victims; for at
that instant a work was assigned to them to do, such as they could
hardly have hoped or prayed for. To find delivered into their hands a
mob of helpless enemies, in an ecstasy of terror, presenting their
unarmed sides in such sort that none turned to defend himself, but
each victim rather seemed to contribute what he could towards his own
destruction--if that was not divine interposition, I know now what to
call it. Miracle or not, in that little space so many fell, and the
corpses lay piled so thick, that eyes familiar with the stacking of
corn or wood or piles of stones were called upon to gaze at layers of
human bodies. Nor did the guard of the Boeotians in the port
itself escape death; some were slain upon the ramparts, others on
the roofs of the dock-houses, which they had scaled for refuge. (Xenophon Hellenica)
The Spartans were then able to capture the town of Lechaeum, though not the
port itself, tore down part of the walls and made a number of incursions into
Corinthian territory taking by assault, first Sidus and next Crommyon. Praxitas
left garrisons in these two
fortresses and finally fortified Epieiceia as a garrison outpost to protect the territory of the allies He then disbanded his troops and himself withdrew to Lacedaemon. When winter arrived he Athenians came with masons and repaired the breach in the walls.
In 391 Agesilaus captured the port of Lechaeum with a joint land-sea operation and in the following year captured Piraeon, on the promontory on the north of the Corinthian gulf which controls the route between Corinth and Boeotia and also captured Sidon and Crommyon on the Saronic Gulf. Corinth was therefore boxed in except on the Argolid frontier. Sparta now controlled the passage through the Isthmus. In 390 Iphicrates led a surprise attack from Corinth on a Spartan mora of 600 hoplites returning to Lechaeum from Sicyon after escorting the men of Amyclae. The repeated assaults of the peltasts supported by hoplites wore out the Spartans in their attempts to close with them, although if the cavalry mora had been handled better the outcome may well have been different. Xenophon says 250 were killed and although not a decisive victory it was suggestive of what skilfully handled peltasts could accomplish against isolated or badly supported hoplites. Agesilaus now left behind a garrison and retired to Sparta in something of a disgrace. Agesilaus must bear most of the responsibility for this disaster for not providing sufficient competent cavalry and had failed to heed the lessons of 423 when Brasidas and his hoplites were mauled by Thracian peltasts after being left unprotected by the allied Macedonian cavalry. The gates out of the Peloponnese were again barred to Sparta and the Boeotians lost interest in peace.
In 389 Agesilaus campaigned in Arcanania on behalf of the Achaeans who were in difficulty against the Arcananians who were allied to the Athenians and Boeotians.
Sparta had realized that the success of its opponents were largely attributable to Persian support. As early as 392, Sparta attempted to come to terms with Persia sending Antalcidas to negotiate with Tiribazus, then satrap in Sardis. The Confederates sent Conon to Tiribazus to argue against the Spartan proposals. Tiribazus was initially favourable to Sparta and imprisoned Conon who died shortly thereafter on Cyprus, but he was soon recalled and replaced by Struthas, who was not favourable to Sparta. In 389 Thrasybulus sailed with 40 ships to the Hellespont and won alliances with Thasos, Samothrace, the Chersonese, and Byzantium and Chalcedon on the Bosporus. This enabled Athens to again collect tolls on traffic from the Black Sea. He then went to Lesbos, killed the Spartan harmost there and won over Clazomenai. Thrasybulos then sailed to Rhodes, where he was supposed to thwart Spartan efforts to regain the island, on the way he levied war contributions from the cities of Asia Minor. At Aspendus, the locals were unhappy at the heavy handed collection tactics and assassinated Thrasybulus. In 388 the Spartan admiral Anaxibius was sent out to act against Athens and Pharnabazus in the northeast and seized merchant vessels. Iphicrates was despatched with 1200 peltasts to harass Anaxibius and ambushed Anaxibius by night as his troops were returning from establishing a garrison in Antandrus and renewed the Athenian control of the region. Persia did not look kindly on any of this, nor with Athens' attempt to help Evagoras of Cyprus in his revolt against Persia. In 390 Antalcidas again travels to Susa to try to negotiate a peace, this time with greater success. The proposal, as last time, had been that the King should enforce a peace in which all Asiatic cities should be subjects of the king, and that all other Greek states should be independent, it was intended to break up the unity of Boeotia under Thebes' leadership, and the recent federal unity of Argos and Corinth. Sparta also received the help of 20 warships from Dionysus of Syracuse. Anatalcidas and Tiribazus returned to Asia Minor in 387 and found the Spartan fleet blockaded at Abydus by Iphicrates. They were able to break the blockade, and, with the help of the Syracusan fleet, blockaded the Athenians in the Hellespont, preventing them from reaching Athens. Meanwhile, trade at Athens was being disrupted by Spartan raids from Aegina. A Congress was held at Sardis, at which Tiribazus read the edict of the King. In it the Persian king claimed possession of all the cities in Asia, plus the islands of Clazomenae and Cyprus, he recognized Athens' rights to Lemnos, Imbros, and Scyros and declared all other Greek cities autonomous. He announced that the King was ready to enforce these terms by force if necessary. The Ambassadors returned to their cities to report the terms of the peace and met at Sparta to declare their acceptance. But the Thebans tried to sign the peace on behalf of the Boeotian cities, which was a violation of the autonomy provisions, and exactly the thing Sparta was trying to prevent ,after some debate, Thebes relented.
The Peace of Antalcidas or the "Kings Peace" meant the end of Corinthian War, the surrender of the Greeks of Asia to Persia, an end of the Argive-Corinthian Union, dissolution of Boeotian League and Sparta's de facto supremacy on mainland Greece. Sparta may well have settled on a mistaken policy, accepting Persian rule over the Asiatic Greeks for support of Spartan hegemony over mainland Greece brought about by Agesilaus' obsession with Theban control over the Boeotian League. In all this Agesilaus was accused of medising, his reply to the charge was that the Spartans were not Medising but that the Persians were Laconising.