In the blood-soaked sand of the Colosseum, the Emperor of Rome held a crescent dart in one hand and the severed head of an ostrich in the other, then walked to the senators' seats and gestured: you're next. Cassius Dio, sitting in those rows, wrote that senators chewed laurel leaves from their wreaths to hide their trembling mouths. Twelve years earlier, Commodus had inherited the most stable, prosperous civilization on Earth from his father, the philosopher-king Marcus Aurelius.

This episode dissects the descent from gold to iron and rust: the first emperor born in the purple rather than chosen on merit, the currency devaluation that bought the Praetorian Guard and bankrupted everyone else, his sister's assassination plot, and the gladiator delusion that ended with a wrestling coach in a bathtub. It closes with the childhood story of the b ...