The article explores the tradition about the unsuccessful attempt of the Spartan harmost Sphodrias to capture Piraeus in 378 BC. Since Sphodrias acted without authorisation, he was brought to a public trial at Sparta. His unexpected acquittal was entirely due to the king Agesilaus. The analysis of the tradition about Sphodrias’ trial leads the author to the conclusion that Agesilaus controlled the entire state apparatus at Sparta, including the judicial board. In Sphodrias’ trial, the opinion of one person, i.e. Agesilaus, decided the outcome of the vote. The acquittal of Sphodrias initiated by Agesilaus is a weighty testimony of the great authority that this king had in the first decades of the fourth century BC (before the battle of Leuctra).