The Spartan politician and naval commander Antalcidas is chiefly known for his part in negotiating The King's Peace (a.k.a. the Treaty of Antalcidas), which concluded the Corinthian War (386 BCE). He seems to have come from a prominent family and may have been related to Agesilaus II by marriage. Earlier, he was Sparta's representative at the Sardis Graeco‐Persian conference (392 BCE) and in 388 negotiated an alliance with Artaxerxes II. As Sparta's admiral (nauarchos), he then blockaded the Hellespont and forced the Athenians and their allies into the negotiations that resulted in the King's Peace. While he seems to have disagreed with Agesilaus, particularly over the king's unrelenting hostility towards Thebes, he carried out several diplomatic missions to Persia. The failure of one such mission in the 360s resulted in his suicide.