Monarchy: feudal period and Medieval French kings conferred the dignity of a peerage on some of their pre-eminent vassals, both clerical and lay. Some historians consider Louis VII (1137–1180) to have created the French system of peers. A peerage was attached to a specific territorial jurisdiction, either an episcopal see for episcopal peerages or a fief for secular ones. Peerages attached to fiefs were transmissible or inheritable with the fief, and these fiefs are often designated as (for duchies) or (for counties). The traditional number of peers is twelve. They are: Archbishop-Duke of Reims, premier peer Bishop-Duke of Laon Bishop-Duke of Langres Bishop-Count of Beauvais Bishop-Count of Châlons Bishop-Count of Noyon Duke of Normandy Duke of Aquitaine, also called Duke of Guyenne Duke of Burgundy Count of Flanders Count of Champagne Count of Toulouse According to Matthew Paris, the Duke of Normandy and Duke of Aquitaine ranked above the Duke of Burgundy. But since the first two were absorbed into the crown early in the recorded history of the peerage, the Duke of Burgundy has become the premier lay peer. In their heyday, the Dukes of Normandy were undoubtedly the mightiest vassals of the French crown. The constitution of the peerage first became important in 1202, for the court that would try King John of England in his capacity as vassal of the French crown. Based on the principle of trial by peers, a court wishing to acquire jurisdiction over John had to include persons deemed to be of equal rank to him in his capacity as either Duke of Aquitaine or Normandy. None of the peers had been specified, but since John's trial required the presence of the peers of France, it can be said that the first two peerages identifiable in the documents would be the duchies of Aquitaine and Normandy. In 1216, Erard of Brienne claimed the County of Champagne through the right of his wife, Philippa of Champagne. Again this required the peers of France, so the County of Champagne is also a peerage. Six of the other peers were identified in the charter — the archbishop of Reims, the bishops of Langres, Chalons, Beauvais and Noyon, and the Duke of Burgundy. The tenth peerage that could be identified in the documents is the County of Flanders, in 1224. In that year John de Nesle entered a complaint against Joan of Flanders; the countess responded that