Vidame de Chartres was a title in the French nobility. There are a few vidame titles in France, of which that of Chartres is probably the best known, because a number of holders have been notable in widely different ways over the centuries. Vidame was originally the name for the commander of a bishop's military force in the Early Middle Ages, when bishops, like other great lords, needed troops for security. The title eventually developed into a heritable noble title, like others linked to a specific estate. The title therefore passed to the new owner when the estate was sold, as happened a number of times in this case.
By the later Middle Ages, the title was held by the owner of the chateau and estate of La Ferté-Vidame (documented by 985), Eure-et-Loir, some 40 kilometres from Chartres. In the 17th century the holder was still supposed to pay an annual fee to the Bishop of Chartres (for holding the land associated with the role, while not performing the duties), ceremonially presented during the mass in Chartres Cathedral on the feast day of the Purification of the Virgin.
The vidame of the day took part in the First Crusade (1095–1099). The title was held by the de Ferrières family by the 12th century. They had acquired it through marriage with the sister and heiress of the 10th vidame of the family of the lords of Étienne. Confusingly, this was an entirely different de Ferrières family to that holding the title in the 16th century. Holders included Guillaume de Ferrières (grandson of the first de Ferrières vidame, c.1150 – ?April 1204), who took part in the Third (1188–92) and Fourth Crusades (1201–4), and died in Romania as part of the latter. He is assumed to be the trouvère (north French troubador poet-composer) recorded only as the "Vidame de Chartres", to whom eight songs have been attributed. Through his sister the title passed to the lords of Meslay-le-Vidame, Eure-et-Loir.