New German School
During his last few years in Berlin, Cornelius wrote music criticism for several major Berlin journals and entered into friendships with Joseph von Eichendorff, Paul Heyse and Hans von Bülow. Despite his long-standing association with Wagner and Franz Liszt (the latter on occasion sought Cornelius's advice when it came to matters of orchestration), Cornelius's relations with the so-called "New German School" of composition were sometimes rocky. For instance, he did not attend the premiere of "Tristan und Isolde", using the premiere of his own opera "Der Cid" as an excuse.