While tennis is now one of the biggest and most-watched international sports in the world, it used to not even use the signature racket it is now known for. Historians believe that tennis was first invented in 12th-century France, where monks would play the game to keep themselves busy. The sport looked a little different than it does today. The biggest difference is that players would use their hands as rackets. They would strike the ball over a net with the palm of their hand, giving the sport its first name, ‘game of the palm’.