<human>:  When did paper money first come into use?
<bot>: Paper money was first used in China in the 7th century. It was called ‘cash’ and was used to pay taxes and buy goods. In Europe, paper money became popular in the 13th century, but it wasn’t widely used until the 15th century. It was then that the first banknotes were printed. These notes were used to pay taxes, and were backed by gold or silver. Paper money was eventually replaced by coins, which were more convenient.