Alcibiades, the son of Cleinias, grew up in the house of his guardian Pericles and was apprenticed to Socrates. He broke with Nicias when the latter became aware of his grandiose plans for a Sicilian expedition, for which he was elected general (415 B.C.). However, he was recalled to Athens to stand trial for the mutilation of the Hermae (busts of Hermes) and for profaning the Eleusinian mysteries.

He escaped to Sparta where he offered his services, encouraging the Spartans to send a general to Sicily and install a garrison at Decelea in Attica (413 B.C.). However, he lost their trust when he urged them to focus their interest on the Aegean and not on the Hellespont.

Later he succeeded the Persian satrap Tissaphernes, with whose support he had tried in vain to secure his return to Athens, where he intended to establish an oligarchic constitution.

In 411/0 B.C. with the support of oligarchic Athenians, Alcibiades was elected general of the Athenian fleet in Samos. For some years he directed Athenian operations in the Hellespont and won an important victory at Cyzicus in 411/0 B.C. He returned to Athens in 407 B.C., the charges of sacrilege were dropped, but after some failures he retired to Thrace, where he tried unsuccessfully to warn the Athenians before the battle at Aegospotami (405 B.C.).

He sought refuge with the Persian Pharnabazus, and was murdered in Phrygia, most probably on the orders of the Thirty tyrants and the Spartan Lysander.