Founded in 1925, the Berlin Radio Choir was already collaborating with such conductors as George Szell, Hermann Scherchen, Otto Klemperer, and Erich Kleiber from its earliest years. Helmut Koch took over as leader after the Second World War and for the first time led performances of numerous Handel oratorios in their unabridged versions. Dietrich Knothe (1982–93) then expanded the repertoire from the Renaissance up to experimental avant-garde works, while Robin Gritton (1994–2001) focused on developing an international profile for the ensemble. Simon Halsey has led the choir since 2001, establishing not only a regular partnership with the Berlin Philharmonic and Simon Rattle but also with the Berlin Radio Symphony Orchestra and the German Symphony Orchestra. Their recordings of Brahms’s German Requiem and the Symphony of Psalms by Stravinsky under Rattle’s baton won the Grammy Award for Best Choral Recording in 2007 and 2008, respectively. The Choir presently numbers 64 members and und gives about 50 concerts each year, including international guest appearances; the group’s focus is on the choral-symphonic repertoire. The Berlin Radio Choir is part of the Radio Orchestra and Choruses Corporation (ROC), which is owned by German Radio, the Federal Republic of Germany, the city-state of Berlin, and Radio Berlin Brandenburg.