From The Kit Kat Club by Ophelia Field:
...he had written the libretto of an opera, Rosmond, about Henry II's lover Rosamond Clifford, and it was to have its opening night at the Drury Lane theatre. 'addison had altered the ending of Rosamond's true story to a falsely happy one: the reunion of Henry II and his murderous wife Eleanor. This was intended to make the opera an allegory for the Act of Union, with Eleanor representing the Jacobites of Scotland coming to be tamed...p.166-67"