Alcibiades was the ward and relative of Pericles, he was also a student of Socrates, who saved his life when they served together in the army.

He was the primary driving influence behind the Sicilian Expedition, winning over support despite the opposition of Nicias, a much more experienced general. It is believed that Alcibiades saw Sicily as more than just an asset against Sparta and that his real goal was to create a permanent Athenian presence on Sicily. Once the Peloponnesian War was over this would allow him to bring Athens into conflict with Carthage, who also had a significant interest in Sicily. If Athens could defeat Carthage, they would be able to expand significantly into the western Mediterranean. For Alcibiades this would make his career as offensive wars generated more supporters at home with the inflow of plunder and later tribute.

Unfortunately Alcibiades lost control of the expedition after he was recalled to Athens to face charges over the mutilation of the herms. The herms were statues of Hermes placed outside doors and they had prominent genitalia, the night before the expedition a large group cut the genitalia off almost all of the statues in Athens. Most believe that it was more than a drunken prank due to the scale of the vandalism. Also most doubt Alcibiades involvement since he would not be looking to damage his expedition. Alcibiades did the smart thing in not returning to Athens when he was accused since his supporters were all with him on the ships, and the Athenian mob could be very harsh in their judgements. However when he went to Sparta and tried to convince them to go to Sicily he became a traitor. Athens later requested him back in desperation and he obliged but again there was a disagreement, this time after the naval defeat at Notium and he retired to family land in Thrace. He was assassinated in a move engineered by Lysander and the Thirty Tyrants.

Alcibiades was an attention seeker, apparently the first time he entered the Assembly he had a quail under his cloak, the bird reacted badly and he ended up chasing it around the Assembly. Alcibiades also managed to get the wife of King Agis of Sparta pregnant. Interestingly enough Thucydides' opinion of Alcibiades's appears to change through his work, some historians theorise that since both lived in Thrace, Alcibiades had a chance to put across his own arguments for his actions.

Alcibiades was an ambitious and charismatic leader of men, had he not changed sides it is possible that the Athenians would have won the Second Peloponnesian War