The Armagnac party was prominent in French politics and warfare during the Hundred Years' War. It was allied with the supporters of Charles, Duke of Orléans against John the Fearless after Charles' father Louis of Orléans was killed at the orders of the Duke of Burgundy in 1407. The party took its name from Charles' father-in-law, Bernard VII, Count of Armagnac, who guided the young Duke during his teens and provided much of the financing and some of the seasoned Gascon troops that besieged Paris before their defeat at Saint-Cloud. Later, John the Fearless was sent back to his lands, and Bernard of Armagnac remained in Paris and, some say, in the queen's bed. He was assassinated in 1419.
Sporadic warfare continued between the Armagnacs and Burgundians for a number of years, although after the Burgundians allied themselves with the English in 1419 and the Armagnacs became interlinked with the cause of Charles VII, the factional rivalry was scarcely distinguishable from the Royal dispute between the French and English monarchies. The terms remained in use until they were outlawed by Charles VII toward the close of the Hundred Years' War, as part of efforts to heal the factional rift.