Quentin Durward by Walter Scott
http://www.gutenberg.org/ebooks/7853
https://en.wikipedia.org/wiki/Quentin_Durward
The plot centres on the medieval rivalry between Louis XI of France and Charles the Bold, Duke of Burgundy. Louis incites the citizens of Liège to revolt against Charles, and they seize and murder Charles's brother-in-law, Louis de Bourbon, Bishop of Liège, under the command of Louis's ally, William de la Marck, who was hoping to install his son in Louis de Bourbon's place (a real historical event which occurred in 1482).
At the time of the murder, Louis is present in Charles' camp at Peronne, hoping to fool him with a false display of friendship. Charles, however, sees through his mask of deceit, accuses him of instigating the uprising, and has him imprisoned. Louis's superior coolness of mind permits him to allay Charles's suspicions and to regain his liberty. In a sub-plot, the Burgundian heiress Isabelle de Croye takes refuge at Louis's court when Charles attempts to give her hand in marriage to his odious favourite Campo-Basso. Louis, in turn, resolves to give her in marriage to the bandit-captain William de la Marck, and sends her to Flanders under the pretence of placing her under the protection of the Bishop of Liège. She is guarded on her journey by Quentin Durward, an archer, who has left behind poverty in Scotland to join the Archers of Louis's Scottish Guard. Quentin prevents the intended treachery and earns Isabelle's love. Charles, though, promises her in marriage to the Duke of Orléans (heir to the French crown) but she refuses, and, in anger, the Duke promises her to whoever brings him the head of de la Marck. This Quentin does with the help of his uncle, Ludovic Lesley, and wins Isabelle's hand.