From Benford's Gilbert and Sullivan Lexicon:
Owing perhaps to The Mikado's great success, Sullivan became more amenable to continuing his collaboration with Gilbert. The Mikado's long run gave the composer time to engage in what he considered his real forte: oratorios and other serious compositions. He also engaged in a good deal of travel and socializing with the upper crust. Gilbert found time to develop a non-lozengian libretto, a parody of old-time blood-and-thunder melodramas, which he titled Ruddygore. Melodramas have been defined as serious plays intended for undiscriminating audiences. In such works conflicts and calamities are more interesting than the characters, who tend to be stereotyped as either good or bad. Much like modern TV shows, one finds in melodramas passion, excitement and action in plenitude, but seldom much in way of motivation (214).
The new opera opened at the Savoy on January 22, 1887. Almost anything following The Mikado would suffer by comparison, and Ruddygore most certainly did. Audiences and critics were less than enthusiastic. Gilbert and Sullivan quickly effected some revisions, among which was to change the spelling of the title to Ruddigore -- considered less offensive to genteel English tastes. The opera then ran for 288 performances, which was not a bad record -- except in contrast to The Mikado's 672.
Ruddigore's place in the hearts of Gilbert and Sullivan devotees is akin to Princess Ida's. Although the opera is among the less well known, it bears repetition and will seemingly always be popular among more experienced Savoyards.
CHARACTERS AND SETTING
Gilbert gives the time as “Early in the nineteenth century.” For reasons to be explained later we can infer that the time should have been no later than 1805.
Ruthven [Sir Ruthven Murgatroyd]: This is an old Scottish family name that should be pronounced “Rivven,” except as noted at the start of the second act. The name has dark overtones. In 1566 William, fourth baron Ruthven, was involved in the murder of David Rizzio, Mary, Queen of Scots’s secretary and suspected lover. Worse yet, in 1600 the Earl of Gowrie, whose family name was Ruthven, kidnapped James VI of Scotland. In retribution, the Scottish Parliament passed an act stating “that the surname of Ruthven sall now and in all tyme cumming be extinguischit and aboleissit for euir.” The law was subsequently relaxed for one branch of the clan. For further details see “Gowrie Conspiracy” in The Encyclopædia Britannica (103).
Ruthven was also the name of the vampire in Polidori’s novel The Vampyre (1819) and two derivatives: Planché and Nodier’s play The Vampire (1820), and Marschner’s opera Der Vampyr (1828). Gilbert used that same name for the villain in one of his own early plays: A Sensation Novel (277).