Castles for Two (1917)

Heiress Patricia Calhoun visits her ancestral home in Ireland, hoping to discover the fairies of whom her grandmother often spoke. Posing as a poor housemaid, Patricia meets impoverished aristocrat Brian O'Neil, who instantly falls in love with her. However, Brian's three sisters demand that he marry a wealthy American woman in order to save his family's estate. As a practical joke, Patricia leads Brian to believe that her spinster secretary is actually the heiress, and finds enjoyment in observing his awkward attempt at a marriage proposal. Ultimately, Patricia's true identity is revealed and Brian is able to marry the woman he loves.