The Vienna boys Choir (German: Wiener Sängerknaben) has a long history and tradition. There are 100 boy choristers between the ages of nine and fourteen, divided into four touring choirs and named after Austrian composers associated with the choir's history, Bruckner, Haydn, Mozart and Schubert. Each choir spends nine to eleven weeks of the academic year on tour. The choirs are of equal standing; the tours, appearances in Vienna and recording projects are shared among them. Each choir has a choirmaster, and two tutors or prefects who travel with the boys. Together, the choirs give around 300 concerts each year, attended by almost half a million spectators around the world. The choir regularly tours Europe, Asia, Australia and the Americas.