The four choirs
For those of you who haven't heard this before, the Vienna Boys' Choir is divided into four sub-groups or touring choirs. 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.
The choirs are named after famous Austrian composers associated with the choir's history, Bruckner, Haydn, Mozart and Schubert. The choir still performs much of their music.