<human>:  Who invented playing cards and when?
<bot>: The earliest known playing cards were invented in China around the year 1000 AD. Playing cards were originally used as gambling tools, but they later became a popular form of entertainment. In the 1500s, cards were made from wood and paper, and were often used for gambling and entertainment. In the 1600s, cards were made from silk and ivory. These cards were often used for playing games such as chess and backgammon.