Together with Wolfgang Steinecke, Lange played a decisive role in the establishment of the Darmstädter Ferienkurse which was completely destroyed by war in 1945.
In Berlin, Lange devoted himself to other musical tasks in addition to his intensive work with the Sing-Akademie: In the Tribune he performed Stravinsky's L'Histoire du soldat in a remarkable series of more than 60 performances at the end of 1950; in 1951 Boris Blacher's Romeo and Juliet was heard in the same theatre and one year later the premiere of Wolfgang Fortner's pantomime The Widow of Ephesus.
In the Berlin Festival Weeks he brought out Claudio Monteverdi's Marienvesper as a German premiere in 1952, and in 1953, L'incoronazione di Poppea in the Hebbel-Theater.
Annual performances of Bach's oratorios on the traditional holidays (St. Matthew Passion, B Minor Mass, Christmas Oratorio), performances of well-known works of the great choral literature, among others by Johannes Brahms, Anton Bruckner, Georg Friedrich Händel, Joseph Haydn, Wolfgang Amadeus Mozart, Robert Schumann, Igor Stravinsky, as well as performances of almost forgotten works, for example Die Israeliten in der Wüste by Carl Philipp Emanuel Bach and sensational first performances by Joseph Haydn, Claudio Monteverdi, Otto Nicolai, Giovanni Battista Pergolesi, Giacomo Puccini, Alessandro Scarlatti and the world premiere of the Te Deum by the young Georges Bizet, which had been lost until then and was discovered by Lange in Paris, as well as performances of contemporary works such as Max Baumann's Deutsche Vesper, Hans Werner Henze's Musen Siziliens (commissioned composition) outline Lange's broad repertoire.
Lange's cultural achievements over a quarter of a century were honoured by the award of the Music Prize of the German Critics (1952) and the Order of Merit of the Federal Republic of Germany (18 September 1967).