THE RECORD
What changed
Early texts warn of saltpetre, sulphur and carbon mixtures; Song sources describe fire arrows, lances and bombs.
EVIDENCE
What remains
Recipes in Chinese treatises, excavated weapons and images document the transition.
WHY IT MATTERS
Why it matters
It reshaped walls, armour and state finance, combining with local weapon systems across Eurasia.
OPEN QUESTION
Where interpretation begins
The path from mixture to cannon was long, and no single Mongol transmission route explains every development.