thumb|Marriage of [[Charles I, Duke of Orléans to Bonne of Armagnac at the Château de Dourdan - from the manuscript Très Riches Heures du Duc de Berry.]]
The Armagnac (, ) faction was prominent in French politics and warfare during the Hundred Years' War. It was allied with the supporters of Charles I, Duke of Orléans against John the Fearless after Charles' father Louis of Orléans was killed on a Paris street on the orders of the Duke of Burgundy on 23 November 1407.
The Armagnac Faction took its name from Bernard VII, Count of Armagnac (1360–1418), Charles' father-in-law. He guided the teen-aged Charles and provided much of the financing and some of the seasoned Gascon troops that besieged Paris before their defeat at Saint-Cloud.
Origins
In 1407, Louis I, Duke of Orléans was assassinated on the order of John the Fearless, Duke of Burgundy. Fearing Burgundian ambitions, the dukes of Berry, Brittany, and Orléans, and the counts of Alençon, Clermont, and Armagnac, formed a league against the Duke of Burgundy in 1410.