Complex sentence: He was famous for his work in the piano trio, with Isaac Stern and Leonard Rose, known as the Istomin-Stern-Rose Trio, with whom he made many recordings, and particularly of music by Beethoven, Brahms and Schubert.
Split into simpler sentences: He was famous for his work in a piano trio, in which he collaborated with Isaac Stern and Leonard Rose. Known as the Istomin-Stern-Rose Trio, the group made many recordings, particularly of music by Beethoven, Brahms and Schubert.