The London Symphony Orchestra (LSO), founded in 1904, is the oldest of London's symphony orchestras. It was set up by a group of players who left Henry Wood's Queen's Hall Orchestra because of a new rule requiring players to give the orchestra their exclusive services. The LSO itself later introduced a similar rule for its members. The orchestra underwent periods of eclipse in the 1930s and 1950s when it was regarded as inferior in quality to new London orchestras, to which it lost players and bookings. By the 1960s it had recovered its leading position, which it has retained subsequently.