In 1868 appeared "Händel und Shakespeare, zur Asthetik der Tonkunst", in which he drew an ingenious parallel between his favorite poet and his favorite composer, showing that their intellectual affinity was based on the Teutonic origin common to both, on their analogous intellectual development and character. The ill-success of this publication, and the indifference with which the latter volumes of his "History of the 19th Century" were received by his countrymen, together with the feeling of disappointment that the unity of Germany had been brought about in another fashion and by other means than he wished to see employed, embittered his later years, though it did not sour his kindly and humane disposition, nor did it in the least affect his sociable temper, and he cultivated refined society to the last. He died in Heidelberg on 18 March 1871.