In early 405 the Spartan general, Lysander, captured the whole of the Athenian fleet. Alcibiades alone had foreseen the danger, but his advice had been ignored. With no fleet left, Athens tried desperately to win support from its few remaining allies, treating them with a level of respect and equality that would have been unthinkable only a decade before.

Meanwhile, the Spartans blockaded the Piraeus with a fleet of their own. The situation was hopeless. Athens' long road to self-destruction was at an end. As the assembly set up a series of show trials to punish their erstwhile leaders, a peace delegation set off for Sparta.

The conditions were severe. Unconditional surrender was far more unusual in the ancient world than it has become in the 20th century, but by any standards the terms amounted to total defeat. To their credit, the Spartans refused to enslave the whole population as many of their allies desired. Nevertheless, the starving Athenians had no choice but to accept the loss of their navy, the dismantling of their great walls and fortifications, and Spartan control of their foreign policy.