Real tennis, also called court tennis or royal tennis, racket sport that is descended from and almost identical to the medieval tennis game jeu de paume (“game of the palm”). Real tennis has been played since the Middle Ages, but the game has become almost completely obscured by its own descendant, lawn tennis. Although real tennis contributed its name and scoring system to lawn tennis, real tennis is now played at approximately 40 courts in the world. The court at Hampton Court palace, where Henry VIII played, is still used. Real tennis is played on an indoor court with four irregularly sized walls, using pear-shaped lopsided rackets to hit cloth balls that are much harder than those used in lawn tennis. Roofs to the court slope over a net that is 1.5 metres (5 feet) high at its sides and 0.9 metre (3 feet) in the middle. The construction of a court is complex and difficult, and the declining number of players discourages the building of new courts. The world real tennis championship is decided by challenge match, in which a player challenges the champion to defend his title. Pierre Etchebaster held the world title from 1938 to 1954, when he retired at the age of 61.