From the Substack post on August 31, 2021, by Aulus.
Alcibiades' was more beautiful with every season, a lover and student of Socrates, and man of great influence throughout Athens. A man prone to relapsing into his intemperance of his pre-Socratic phase, he was nevertheless confident enough in himself to suggest something insane…
The Athenians and Spartans were once again at peace, the more ruthless days of Archidamus were now done. For now. Alcibiades suggested the Assembly send 2,000 Hoplites and more allies to Sicilia, to conquer Syracuse at the request of Athens' allies there. It was opposed by Nicias, but in the end he was overruled. Three generals were appointed, Alcibiades, Lamachus (fifty years a career soldier) and Nicias. Nicias protested his appointment but it was for nought.
They were about to set out until Alcibiades was rocked by scandal when the Hermai (statues of Hermes, to guide travellers) were defaced. His political enemies refused him a trial, in part weakening the expedition.
Three generals, three strategies. Nicias stated they shouldn't do much but parade around to show Athens' might with its new fleet and army. Alcibiades proposed they go around and march to Syracuse causing rebellion among the other Greek colonies. Lamachus at first wanted to attack the enemy directly and quickly take them by surprise. This would probably have worked as Syracuse's main advantage was in cavalry, which a landing at the city's port would nullify. Lamachus decided to cool tensions and went with Alcibiades.
After Alcibiades' recall and subsequent defection, they fought a quick battle and won and then hunkered down for winter. Next, they began to build a wall to Siege Syracuse and cut off its sea access. It didn't work. Syracuse built a perpendicular wall and Lamachus and a few men were stuck in between. Slaughtered like cattle.
Nicias was not a military man, was sick, and out of money. He requested either to be recalled or to be reinforced. Athens chose the latter, disregarding Nicias's concerns. Demosthenes who smashed the Spartans at Pylos and with Kleon's help at Sphakteria was sent with more men and money. He decided to attack a Syracusan defense on the mountain-hill of Epipolae. Demosthenes was successful at first, surprising and destroying the first line of defense and the second line was put to flight. However, due to the dialect of their allies and the dark many died by their allies' hands. Even worse some plunged off the mountain. The Syracusans quickly regrouped and outflanked Demosthenes, putting many to the spear. Others to the sword and hoof. They quickly ran.
Their fleet had been destroyed or beached. Nicias had warned Demosthenes of the assault on Epipolae but it was done. Nicias determined retreat to Athens would result in execution and decided to try and retreat. The Syracusan cavalry tore them to shreds like a lion may kill a goat. They both surrendered to Sparta, knowing the Syracusans would execute them. Ultimately the Spartan general's order to spare them was ignored. The Athenians, Italians and Sicilians and other Greek allies numbered 7,000 and so were stored in a large quarry. All those Greek allies were sold into slavery. The Athenians and Greek colonists were starved, or died of disease.
When the first messenger arrived the Atticans refused to believe what had happened, the messenger initially went to a barber to gossip as was the cultural norm. The barber heard this and ran to the Athenian assembly to interrupt their proceedings and tell them. They were shocked. No one believed him. Then the escapees of the quarry arrived, starved, weakened and weary-eyed. Then there was unceasing wailings.
And so the Athenians could not believe the fate, of which Nicias had so often foretold to them.
— Plutarch, Life of Nicias