Arrangements by Johann Sebastian Bach
Johann Sebastian Bach appreciated good compositions by other masters, as is clear from contemporary reports and from a glance at what remains of the contents of his music library. It is a fact, however, that in copies of other composers' works which he made for his own use he seldom failed to make corrections here and there. For performances in Leipzig pieces sometimes had to be altered to comply with local liturgical regulations. Sometimes the text or the scoring did not comply with Bach's expectations. The best example of this is provided by the famous Stabat Mater by Giovanni Battista Pergolesi, which Bach adapted for a performance as a Protestant penitential composition with German words and an enlarged orchestra. Bach's choice of compositions and his versions of them make the contents of his music library an equally valuable and revealing repertoire for performance.