The Pirates of Penzance or The Slave of Duty by William Schwenk Gilbert is about Samuel the pirate lieutenant and his ship of pirates. Excerpt: "Scene. A rocky seashore on the coast of Cornwall. In the distance is a calm sea, on which a schooner is lying at anchor. Rock L. is sloping down to L.C. of the stage. Under these rocks is a cavern, the entrance to which is seen at first entrance L. A natural arch of rock occupies the R.C. of the stage."