In 1918 when Austria changed from the Austrian-Hungarian empire to the Austrian Republic, the Court Opera became the Vienna State Opera, with the musicians in the orchestra and the singers in the chorus members of Austrian public services. Beside their official duties the members of the orchestra constitute a private society, the Vienna Philharmonic Orchestra, founded in 1842 by members of the orchestra of the Court Opera, to provide an outstanding concert orchestra for Vienna. The Vienna Philharmonic consists only of musicians who were members of the orchestra of the Vienna State Opera, but not each member of this orchestra is necessarily a member of the Vienna Philharmonic. Membership of the world-famous Vienna Philharmonic Orchestra demands the special agreement of all colleagues. In 1927 the chorus of the Vienna State Opera founded a private choral society called the Konzertvereinigung Wiener Staatsopernchor to provide an outstanding concert choir in addition to the singers' duties in the Opera House. The orchestra and the chorus of the Vienna State Opera take part in every rehearsal and performance of the Vienna State Opera during the season from 1st September to 30th June. For all performances apart from their official duties, concerts in Vienna, on tour or special appearances, for example at the Salzburg Festival or for studio recordings, they use their private names, the Wiener Philharmoniker (Vienna Philharmonic) and Konzertvereinigung Wiener Staatsopernchor (Concert Union of the Vienna State Opera Chorus). The BÃŒhnenorchester der
