1233
Kaifeng falls and Jin dynasty collapses
After a winter-long siege punctuated by gunpowder shells and outbreaks of plague, the Jin capital surrendered to the joint Mongol and Song armies. The last Jurchen emperor hanged himself in a monastery the next year, ending a dynasty that had ruled north China for over a century. The city's fall released a flood of refugees southward and scattered Jin artisans and scholars across the steppe.
Kilwa Sultanate dominates East African gold trade
The Swahili city-state of Kilwa, on an island off the Tanzanian coast, seized control of Sofala's gold exports from Great Zimbabwe. Its sultan minted the first sub-Saharan African coinage, copper and silver coins stamped in Arabic, and built the great domed mosque that Ibn Battuta would later admire. Kilwa's coral-stone merchant houses rivaled those of any Indian Ocean port in their elegance.
Coal mining expands in northern England
Monasteries and landlords in Northumberland and Durham began systematic extraction of surface coal seams, called sea coal because it was shipped south along the coast to London. The fuel was cheaper than charcoal but produced acrid smoke that prompted the first recorded complaints about air pollution in English history. By century's end, London's air quality had deteriorated enough that Queen Eleanor reportedly fled Nottingham Castle to escape the fumes.
Mongols use gunpowder bombs at Kaifeng
Defending Jin soldiers reportedly used thunder-crash bombs and fire lances against Mongol besiegers, early deployments of gunpowder weapons. The technology would spread with Mongol armies to the western ends of their empire and transform warfare within two centuries. Chinese accounts describe iron-cased bombs launched from catapults that shattered upon impact, filling the air with metal shards and thick smoke.