Real tennis is the original racket sport from which lawn tennis is descended; although the sport enjoyed its heyday in the 16th and 17th centuries (depiction pictured), it is still played on a small number of active courts, most prominently in the United Kingdom, France (where the sport is known as jeu de paume), Australia (royal tennis), and the United States (court tennis), amongst which the site of the real tennis world championship typically rotates. The term tennis derives from the French imperative tenez (take it, the injunction given a player to receive a serve by the server), and the history of the sport is thought to date to 12th century France, where it is thought to have evolved variously from the sports palla, fives, pelota, and handball, and when it was played with a gloved hand and ball; origins of the shape of real tennis court, though, are disputed, and are understood either as related to the square shapes of medieval city streets or to courtyards at monastery cloisters, where the sport was commonly played. The game spread rapidly across Europe—in 1600, the Ambassador to France of the Republic of Venice reported Paris alone to comprise 1800 courts—and the rules and designs, including the use of a racket instead of a hand, were stabilized by the late 16th century. The formalized rules involved a system of scoring similar to that of lawn tennis, with the first player to achieve six games garnering a set and the first to achieve three sets capturing the match. Play takes place on a doubly asymmetric court; either end of the court is dissimilar from the other—the service is made always from one end—and the left and right sides of each court are also different. The court, a jeu à dedans, is usually 110 feet (34 m) long and 32 feet (9.8 m) wide and enclosed by walls on all sides, of which three are sloping roofs (penthouses) with various openings and a buttress (tambour), off of which shots may, and in the case of the serve, must, be played.