Battle of Gaugamela
Decisive 331 BCE battle where Alexander of Macedon broke the army of Darius III of Persia, opening the Achaemenid heartland. A textbook use of oblique advance and a timed cavalry breakthrough against a much larger force.
Deployment
Darius picks a flattened plain to use his chariots and vast numbers; Alexander refuses a night attack and deploys echeloned, his line angled right.