Where did paper money originate?

The answer

Paper money was invented in China during the Tang Dynasty (7th century CE), when merchants began depositing heavy copper coins with trusted agents in exchange for paper receipts. By the Song Dynasty (960–1279 CE), the government issued official banknotes called jiaozi - the world's first government-backed paper currency. Marco Polo was astonished by the concept when he visited in the 13th century, but it took Europe another 400 years to adopt the idea.