The first historical reference to Hermocrates is at the congress of Gela in 424 BCE, where he gave a speech demanding the Sicilian Greeks stop their quarreling.

In 415 BCE, he proposes a coalition that would even include non-Sicilian cities (as well as non-Greek cities such as Carthage) in an alliance against Athens.

Originally conceived in perfectly acceptable terms, a force of sixty ships, the expedition as ultimately sent is too ambitious, comprising a huge fleet of one hundred and forty ships—one hundred of them Athenian—reinforced by an additional sixty.

Athens has sent two hundred and fifty cavalrymen without mounts, but horses secured locally in Sicily bring the total to six hundred and fifty; Athens has also sent thirty mounted archers.

This total is respectable for a state that has never been a strong cavalry power but is barely more than half of the twelve hundred fielded by Syracuse.

This disparity neutralizes Athens' early successes in the field, as harassment by Syracusan cavalry makes pursuit of the enemy by victorious Athenian infantry a dangerous matter.

Alcibiades gone and Lamachus dead in action leaves sole command to an ailing Nicias, who continues an ineffective campaign around Syracuse, the defenders' efforts blocking completion of the wall his forces attempt to build around the city.

The Syracusan expedition spirals into disaster.