Chinese alchemists hunting the elixir of life found something louder instead: the formula that ended the castle, built empires, and armed the modern age.
Around 850, Taoist alchemists of Tang China — men seeking the elixir of eternal life — recorded a formula that did the opposite of granting life: saltpeter, sulfur, and charcoal, mixed in the right proportions, exploded. The earliest recipe appears in a mid-ninth-century Taoist text, with a warning that the mixture had “burned the alchemists’ hands and faces.” They called it huoyao — fire medicine. The search for immortality had manufactured the most efficient killer in history.
