context: The current game of tennis was developed in England in the mid-19th century. [1] The species first spread in English-speaking countries, especially among the upper classes. Today, tennis is an Olympic sport that is estimated to have around 50 million fans worldwide. Tennis is also a popular form of bench sports: especially professional-level Grand Slam tournaments attract large spectators. There are four of these tournaments around the world, attracting the best tennis players each year. Doubles and doubles are played in the same tournaments, so players can choose to play in singles and doubles in the same tournament. Tennis also has a number of rules that have changed over the years.
question: In what year was tennis invented?
answers.text: in the mid-19th century