The Paris Opera Ballet is one of the most prestigious and oldest classical dance companies in the world. Its roots go back to the dances and practices of court life of Louis XIV. Originally, in 1669, the corps de ballet was integrated into the Royal Academy of Music. Today it is part of the Opéra national de Paris. With 154 dancers they perform over 180 performances per season. The dancers of the ballet have mostly been trained in the Paris Opera Ballet School, considered one of the best in the world. The ballet of the National Opera of Paris recruits very few from outside, which serves to maintain the unity of style of French dance. Notable dancers involved in the company include Serge Lifar, Rudolf Nureyev, and Sylvie Guillem.