“Choral / Wer nur den lieben Gott läßt walten," choir and orchestra, 1829

Donated in 1994, the Leon Robbin Collection of Music Manuscripts and Letters of Composers consists of over 800 autographed manuscripts and letters by composers, musicians, and conductors. Collection highlights include autograph manuscripts by many of the most important Romantic era composers, including Ludwig van Beethoven’s sketches for his Piano Sonata No. 23 in F minor "Appassionata," a full set of handwritten parts for Robert Schumann’s String Quartet in A minor op. 41 no. 1 (Heavily edited by the composer, the first edition of the work was printed from this set), and unpublished works by Ignaz Moscheles.

Other notable composers whose musical materials are represented in the collection include Hector Berlioz, Sir Edward Elgar, Alexander Glazunov (or Aleksandr), Charles Gounod, Franz Liszt, Pietro Mascagni, Jules Massenet, Ignaz Moscheles, Jacques Offenbach, Gioachino Rossini, Camille Saint-Saëns, Pablo de Sarasate, Franz Schubert, John Philip Sousa, Johann Strauss II, Richard Strauss, Giuseppe Verdi, and Richard Wagner.

Additionally, the collection also includes autographed correspondence by Johannes Brahms, Max Bruch, Cécile Chaminade, Gustave Charpentier, Claude Debussy, Gabriel Fauré, Felix Mendelssohn, Giacomo Puccini, Sergei Rachmaninoff, Maurice Ravel, and Ralph Vaughan Williams.

Robbin established an endowment for the further acquisition of musical manuscripts for Georgetown Library.