The Spartan empire began with the decisive victory of Ægospotami in the Hellespont (September or October 405 B.C.). The whole power of Athens was thus annihilated, and nothing remained for the Lacedæmonians to master except the city itself and Piræus; a consummation certain to happen, and actually brought to pass in April 404 B.C., when Lysander entered Athens in triumph, dismantled Piræus, and demolished a large portion of the Long Walls. With the exception of Athens herself—whose citizens deferred the moment of subjection by an heroic, though unavailing, struggle against the horrors of famine—and of Samos, no other Grecian city offered any resistance to Lysander after the battle of Ægospotami; which in fact not only took away from Athens her whole naval force, but transferred it all over to him, and rendered him admiral of a larger Grecian fleet than had ever been seen together since the battle of Salamis.
The allies, especially Thebes and Corinth, not only relented in their hatred and fear of Athens, now that she had lost her power—but even sympathised with her suffering exiles, and became disgusted with the self-willed encroachments of Sparta; while the Spartan king Pausanias, together with some of the ephors, were also jealous of the arbitrary and oppressive conduct of Lysander.
We have learned from dark, but well-attested details, to appreciate the auspices under which that period of history called the Lacedæmonian empire was inaugurated. Such phenomena were by no means confined within the walls of Athens. On the contrary, the Year of Anarchy (using that term in the sense in which it was employed by the Athenians) arising out of the same combination of causes and agents, was common to a very large proportion of the cities throughout Greece. The Lacedæmonian admiral Lysander, during his first year of naval command, had organised in most of the allied cities factious combinations of some of the principal citizens, corresponding with himself personally. By their efforts in their respective cities he was enabled to prosecute the war vigorously, and he repaid them, partly by seconding as much as he could their injustices in their respective cities, partly by promising to strengthen their hands still further as soon as victory should be made sure.
In the greater number of cities, he established an oligarchy of ten citizens, or a decarchy, composed of his own partisans; while he at the same time planted in each a Lacedæmonian harmost or governor, with a garrison, to uphold the new oligarchy. The decarchy of ten Lysandrian partisans, with the Lacedæmonian harmost to sustain them, became the general scheme of Hellenic government throughout the Ægean, from Eubœa to the Thracian coast towns, and from Miletus to Byzantium. Lysander sailed round in person with his victorious fleet to Byzantium and Chalcedon, to the cities of Lesbos, to Thasos, and other places—while he sent Eteonicus to Thrace for the purpose of thus recasting the governments everywhere. Not merely those cities which had hitherto been on the Athenian side, but also those which had acted as allies of Sparta, were subjected to the same intestine revolution and the same foreign constraint. Everywhere the new Lysandrian decarchy superseded the previous governments, whether oligarchical or democratical.
In what spirit these new decarchies would govern, consisting as they did of picked oligarchical partisans distinguished for audacity and ambition—who, to all the unscrupulous lust of power which characterised Lysander himself, added a thirst for personal gain, from which he was exempt, and were now about to reimburse themselves for services already rendered to him—the general analogy of Grecian history would sufficiently teach us, though we are without special details. But in reference to this point, we have not merely general analogy to guide us; we have further the parallel case of the Thirty at Athens, the particulars of whose rule are well known and have already been alluded to.