In addition to Gilbert, Clay's librettists during his 24-year career included B. C. Stephenson, Tom Taylor, T. W. Robertson, Robert Reece and G. R. Sims. The last of his four pieces with Gilbert was "Princess Toto" (1875), which had short runs in the West End and in New York. Clay's other compositions include cantatas and numerous individual songs. His last two works were both successful operas composed in 1883, "The Merry Duchess" and "The Golden Ring". He then suffered a stroke that paralysed him at the age of 44 and ended his career.