Gilbert did, in fact, conclude an agreement with Field, and the first published libretto advised: "Caution to American Pirates.—The Copyright of the Dialogue and Music of this Piece, for the United States and Canada, has been assigned to Mr. Field, of the Boston Museum, by agreement, dated 7th December, 1871." If Field mounted the work, however, the production has not been traced. Gilbert's concern about American copyright pirates foreshadowed the difficulties he and Sullivan would later encounter with unauthorised "pirated" productions of "H.M.S. Pinafore", "The Mikado" and their other popular works. In any case, the libretto was "published and circulated" in London in mid-December.