Paper money existed in China centuries before Europe's first banknote

Under the Song dynasty, around the turn of the 10th and 11th centuries, Chinese merchants started issuing written receipts for metal deposits to avoid hauling heavy copper coins over long distances — over time, the government took over the system and began issuing official paper money.

The twist: the first true banknotes in Europe didn't appear until the 17th century, in Sweden — roughly six hundred years after China already had a developed, state-run economy running partly on paper money.

The Chinese system wasn't immune to the problems that later hit Europe too — excessive paper money issuance under successive dynasties led to episodes of severe inflation, to the point that certain periods partially abandoned it in favor of metal again.

The stakes: paper (or really, mostly digital) money feels obvious today, but it's one of the oldest examples of how "modern" financial solutions are often, in reality, very old ideas rediscovered.