From Benford's Gilbert and Sullivan Lexicon:
Gilbert and Sullivan both tried other partners following their work on Utopia Limited. None met with much success, and so they made one more combined effort: The Grand Duke, which opened at the Savoy on March 7, 1896, and ran for a mere 123 performances. Neither partner, it appears, had put his heart into the effort. Some lines were cut after the initial performance, but stronger measures would have been appropriate.
The Grand Duke is a much neglected opera. Its principal shortcoming is that it is too long. Its principal virtue grows out of that very shortcoming: a competent director can omit songs, chop paragraphs of dialog, and come out with a jolly evening’s entertainment. Try it; you’ll see.
The Grand Duke was Gilbert and Sullivan’s last collaboration. In ever-failing health, Sullivan died on November 22, 1900, at the age of 58. Carte died the following April, aged 56. Gilbert lived on as a country squire and was finally knighted in 1907. He died on May 29, 1911, at the age of 74. The triumvirate left to posterity their delightfully crafted operas. Now, more than a century later, those operas are still admired and lovingly presented by hundreds of amateur performing groups all over the English-speaking world. How surprised and delighted Gilbert, Sullivan, and Carte would be if they could but know. True, Gilbert would growl about directors taking liberties with his lines; Sullivan would be distressed with some of the tempi accorded his scores; and Carte would lament his inability to collect continuing royalties. Still, on the whole, they would derive great satisfaction from the lively current Geeandessian scene.