The Battle of Mantinea in 418 BC was the largest hoplite battle of the Peloponnesian War. The one-sided Spartan victory over their rivals secured Spartan hegemony over the Peloponnesians; and confirmed their reputation as the foremost soldiers in Hellas.
The prime agent behind the anti-Spartan alliance that collapsed at Mantinea was the Athenian Alcibiades son of Cleinias. A kinsman of the late Athenian leader, the renown Pericles, Alcibiades was perhaps the most charismatic politician of his generation. He had wealth, wit, good looks and boundless ambition. While not a great public speaker, he was charming and persuasive in private conversation. Unfortunately for Athens and his own fortunes, he was also completely lacking in scruples; and his primary loyalty was to no one other than himself.
Herm portrait of the young AlcibiadesFollowing the failure of his efforts to sabotage Spartan power in the Peloponnese, he began to champion another project; one that would thrust him into a position of great influence and responsibility in the Empire. In 415 BC, delegates from the Ionian/Elymian city of Segesta in Sicily requested Athenian support in their war against neighboring Selinus; asking for a force of 60 triremes, the cost of which they offered to pay for a year. Alcibiades very quickly became the champion for this proposed intervention in Sicily; arguing for a military expedition to not only aid Segesta, but for subduing the entire island!
This opening of a new war, when the war against Sparta and her allies was yet smoldering and likely to erupt anew was foolish in the extreme….