The work is a hybrid: the first third relates developments and battles within Poland, the remainder of the book serves as a novel of manners describing how Thaddeus, having befriended a British soldier in the Russian army and learned from his mother that he himself is half English, flees to London to begin a new life.

Porter wrote that her goal was "to exhibit so truly heroic and enduring a portrait of what every Christian man ought to be"; she felt obliged to look at the past and to Poland because such people were "extinct" within Britain in her time.

[2] Written during a lull in the Napoleonic Wars, Thaddeus of Warsaw includes numerous speeches and scenes arguing for a spirited defense of constitutional government against absolutism and criticizes the perceived dilettantism of the English aristocracy.

[4] The German edition was praised by Tadeusz Kościuszko,[5][dubious – discuss] the inspiration for the "Thaddeus" of the title and a hero of the American Revolution, and earned Porter a ladyship from the King of Württemberg.

This penury arose because the rights to Thaddeus and her other stories were – after protracted litigation – no longer held by Porter but belonged to her various publishers, including Owen Rees,[5] Richard Bentley, and George Virtue.