"Princess Ida, or Castle Adamant" opened on 5 January 1884 at the Savoy Theatre and ran for 246 performances. It is the only three act Gilbert and Sullivan Opera and the only one with dialogue in blank verse. This is because Gilbert based his libretto on his earlier play The Princess which, in turn, he described as "a perversion" of Tennyson's poem of the same name.
It was produced between Iolanthe and The Mikado when its creators were at the height of their powers. The score is Sullivan at his best, and some people consider that Gilbert's libretto contains some of his funniest lines.
Prince Hilarion had been married in babyhood to Princess Ida, daughter of King Gama. The Princess, however, has set up a college for women from which all men are barred. Hilarion and his friends infiltrate the castle and ultimately the men, led by Hilarion's father, King Hildebrand, stage a full-scale invasion. Ida is abandoned by her women and finally surrenders to her Prince.