"All my strength is gone." Joseph Haydn wrote these words on the final page of his unfinished last string quartet. One can hardly believe him when one listens to this new release by the Leipzig String Quartet - and encounters a composer in full possession of his creative powers. There is nary a trace of the infirmity of old age or fading inspiration; rather, the master draws on all the rich experience of his long artistic life. "I am old and weak" - this self-quotation from his song "Der Greis" (The Old Man) seems to be pure irony.