Adelgitha; or, The Fruits of a Single Error is a gripping Gothic tragedy by Matthew Lewis, centering on the harrowing tale of a fallen woman who faces relentless blackmail from a tyrant after rejecting his advances. Set against the backdrop of High Middle Ages Otranto, the play features historical figures like Robert Guiscard and Michael Ducas, adding depth to its themes of treachery, madness, and despair. While the work may not be refined in every aspect, its emotional intensity and exploration of the consequences of a single error resonate powerfully today.