From Benford's Gilbert and Sullivan Lexicon:
Ruddigore’s disappointing reception accentuated Sullivan’s distaste for further collaboration with Gilbert. Hailed as the Mendelssohn of his day (for his serious compositions), Sir Arthur found greater attractions in hobnobbing with the nobility at soirees, racetracks, and gambling casinos. Always the driving force behind the pair, Gilbert tried in vain to reintroduce the lozenge plot. Sullivan refused, his back stiffened by Queen Victoria’s offhand suggestion that he write a grand opera. Carte, meanwhile, refloated H.M.S. Pinafore at the Savoy as he strained to hold his partners together. Then Gilbert hit on the idea of an opera set in the Tower of London during the reign of Henry VIII (1509-1547). Gilbert conceived a romantic, adventuresome plot and an interesting cast of characters. Sullivan was pleased, and the two collaborators stepped back into harness. Carte kept the Company together with other revivals until October 3, 1888, when the Savoy’s curtain went up on The Yeomen of the Guard. Although the new opera was initially well received and ran for 423 performances, Gilbert, and more particularly Sullivan, were disappointed that it was not another Mikado in the public’s esteem.
The Yeomen of the Guard holds a special place in the Savoy canon, being unique in its mixture of comedy and pathos. The jester, Jack Point, contains a good deal of Gilbertian self-portraiture, and several of the other characters are recognizably human –– in contrast to so many of Gilbert’s farcical portraits. In their later years, both Gilbert and Sullivan counted Yeomen as their favorite collaboration (163, 318).