The title of vidame is an odd feudal relic, of which a half-dozen examples survived to the end of the French Old Regime.
In Carolingian times, before the feudal era, important clerics such as bishops and abbots held important estates, but were forbidden by canon law from participating in the judicial and military aspects of life. To take their place, they appointed individuals to protect and manage their temporal interests: the advocati or vicedomini. In the 10th c. these terms are used indifferently, but in the 11th century the term of avoué is reserved for protectors of abbeys, while that of vidame for appointees of bishops. Oftentimes, the avoués were powerful local lords who added that function to their others (the king of France, as count of Vexin, was the avoué of the abbey of Saint-Denis). Endless conflicts between them and the abbeys led to a progressive curtailments of their powers by the king, and by the 13th century the institution has virtually disappeared.
By contrast, the vidames were not prominent lords, and exercised their powers under the close control of the bishop. Originally appointed officers, they became hereditary like all other offices in the feudal system, passing to the eldest son and by default to the eldest daughter (the wife or daughter of a vidame was a vidamesse). As Loyseau ( Taité des Seigneuries, 1608, p. 153) says, the vidame is to the bishop what the viscount is to the count. Their role was to manage and protect the estates of the bishopric, to exercise in his name the episcopal jurisdiction, to represent him at the count's court, to lead the bishop's troups in battle. The lordship of the vidame consisted in a house near the episcopal palace and a territorial domain in the city or nearby countryside: thus, the vidamé of Chartres consisted in a parcel in the city (located within the episcopal gardens in the 17th c. on the Grande Rue) and the lordship of La Ferté-Arnault, renamed La Ferté-Vidame. Oftentimes, the title of vidame was seen to be attached to the lordship, and the family holding the title took the name of the lordship rather than that of the bishopric.
Not all bishoprics had a vidame, by far; and the institution seemed to have existed mainly in Northern France, though some examples are known in England and the Low Countries. Some bishoprics had a vicomte (Noyon), others had an avoué (Thérouanne), while Reims had both a vidame and a vicomte. The known vidamés are the following:
Over time, the canonical restrictions were removed and the raison d'être of the vidame disappeared. The title remained as a curious relic, and a handful of vidamés survived until the Revolution of 1789.
Those are the only titles for which I have found some trace in genealogies.
The title of vidame d'Amiens was attached to the land of Pecquigny. The heiress to the family of Picquigny, Marguerite, married Robert d'Ailly in 1342. The d'Ailly family ended with Charlotte-Eugénie, who married in 1620 Honoré d'Albert, maréchal de France, duc de Chaulnes (sometimes called Chaulnes-Pecquigny) in 1621 (†1649). His eldest son Henri-Louis was titled vidame d'Amiens before succeeding to his father. The title of Chaulnes became extinct in 1698 with his second son.
The inheritance passed to the descendants of the first duc de Chaulnes' eldest brother, Charles, duc de Luynes in 1619. The heir was the 3d duc de Luynes, who substituted his second son Louis-Auguste to his succession: members of this line bore the title of vidame d'Amiens until Marie-Joseph-Louis (1741-93), last of the second line of Chaulnes.
An agreement of perpetual substitution between the eldest branch of Luynes-Chevreuse and the junior branch of Chaulnes had been passed in 1732, and ratified by Letters Patent of 1733 (see more details). As a consequence, the inheritance of Chaulnes reverted to the eldest line of Luynes. In the 19th century, the grandchildren of the 8th duc split again the inheritance, with Luynes going to Charles-Honoré (1845-70) and Chaulnes-Pecquigny to his brother Paul-Stanislas (1852-81). The latter's grandson Emmanuel died childless in 198?, and the inheritance returned to the eldest line. Presently, the 11th duc de Luynes is Philippe (b. 1905), whose eldest son Jean is duc de Chevreuse and his younger son Jacques duc de Chaulnes. Presumably, the latter might be called vidame d'Amiens.
The vidamé de Beauvais was attached to the land of Gerberoy. At the extinction of the male line in the late 12th century the bishop of Beauvais united the title to the see; this was contested by the sister of the last vidame, until a settlement in 1240 ratified the decision.
In 1698 a François Guillaume, conseiller in the Parlement de Paris, held the title. A list of the vidames of Châlons is in Félix Senn: L'institution des vidamies en France (Paris, 1907).
The vidamé de Chartres was in the family of the lords of Meslay; a fairly famous poet in the 13th century was the vidame de Chartres. The sister of the last male was Jeanne de Chartres, dame de Meslay, who married in 1374 Robert de Vendôme (of the Montoire family, who had married the heiress to the old countal family of Vendôme). Their children bore the title of vidame de Chartres in succession until François de Vendôme, vidame de Chartres (†1562), a prominent Protestant leader. His aunt Louise married in 1519 Jean de Ferrières, lord of Maligny. Her son Jean, vidame, died childless and her daughter Béraude (†1618) married in 1559 Jean de la Fin, lord of Beauvoir-la-Nocle (†1599). Their son Pregent de la Fin, vidame de Chartres (†1624) participated in plots against Louis XIII and, at his death, his estates were taken over by his creditors.
At Louis XIII's behest Claude de Rouvroy, 1st duc de Saint-Simon (1607-93), purchased the vidamé of Chartres. It became the title of the eldest son in the Saint-Simon family, born by Louis (1675-1755) the famous memorialist, then his son Jacques-Louis (1698-1746), duc de Ruffec. The latter's only daughter Marie-Christine (1728-74) married Charles-Maurice de Grimaldi, younger son of the prince of Monaco, titled comte de Valentinois, who inherited the title, and died childless.
The vidamé of Laon was in the hands of Baudoin, lord of Clacy and Chaufery, whose heiress Marie married Hugues de Chatillon, lord of Rosoy. Their son Gaucher was vidame de Laon, his daughter Marie married Jean de Craon, lord of Dommart. Together, they sold the title to Ferry Cassinel, bishop of Auxerre, in 1389. He in turn ceded it to his nephew Jean de Montagu (1363-1409), officially son of Gérard de Montagu (ennobled in 1363), but in fact illegitimate son of Charles V and Biette Cassinel. Jean de Montagu became vidame de Laon in 1390, and was beheaded in 1409. His son Charles (1396-1415), vidame, died at Agincourt, and Isabelle, his daughter by Catherine d'Albret (daughter of the constable of France killed at Agincourt) married in 1398 Jean de Roucy (also killed at Agincourt). Jeanne de Roucy, their heiress, married Robert de Sarrebruck, sire de Commercy. Their son Jean, vidame (†1497) was succeeded by Robert, whose daughter Catherine received Roucy and the vidamé as her share of the inheritance. She married in 1505 Antoine de Roye (killed at Marignano in 1515), and their son Charles de Roye (1510-51) left two daughters: Eléonore brought the lordship of Conti in the Bourbon family, while Charlotte brought Roye and the vidamé to her husband Francois de La Rochefoucauld, on condition that the name and arms be changed to Roye de La Rochefoucauld. Their posterity include Charles de Roye de La Rochefoucauld (†1605), François (†1680) whose younger son Henry (†1652) bore the title of vidame de Laon, Frédéric-Charles (†1690) whose younger son Guy bore the title of vidame de Laon (†1684), François (†1721) and François, vidame de Laon (†1725). The last vidame's two daughters were Elisabeth married in 1737 to Francois-Joseph de Béthune, duc de Charost whose line ended with Edme (1770-94), and Francoise-Pauline married in 1740 to Louis-Antoine de Gontaut, duc de Biron (1701-88), childless.
Vidame de Lanoy, son of the comtesse de Roussi, reported in Dec. 1716.
Nicolas d'Angennes, lord of Rambouillet, was vidame du Mans in the early 17th century. His son Charles, titled marquis de Rambouillet and vidame du Mans (†1652) left a daughter Julie-Lucie, married to the duc de Montausier. Either they, or their heiress Marie-Julie (married to the duc d'Uzès) sold the title to Henri-François de Vassé, baron de la Roche-Mabille (†1684), whose successors Louis-Alexandre (†1684), Emmanuel-Armand (†1710) and Jacques-Armand bore the title. The family became extinct in male line in 1844.
The origins of the title are unclear but very old. The existence of a single title for all Normandie may be due to the fact that, early on, the duke of Normandie assumed the role of protector of ecclesiastical lands for his whole duchy.
The title belonged to the family of Pavilly, whose earliest member is attested in the 7th century! Marguerite de Pavilly married in 1280 Robert d'Esneval; a later Robert d'Esneval died in 1346 leaving Jeanne, who married Gauvin de Dreux, head of the royal family of Dreux (killed at Agincourt). The heir to the Dreux line Anne de Dreux married in 1528 André de Prunelay (†1581), their son Charles, titled vidame de Normandie (†1624) left a daughter Françoise de Prunelay, married in 1615 to Anne de Tournebut. their daughter Marguerite de Tournebut married in 1644 Charles le Roux, and left her title of vidame de Normandie in 1677 to her son Robert le Roux, baron d'Esneval and Acquigny. The line of Esneval ended with Esprit-Robert, born in 1777, who left only daughters.
Mentioned as one of the titles of Antoine-Paul-Jacques de Quélen de Stuer de Caussade, duc de La Vauguyon (1706-72) (e.g., Levantal, p. 705).
The coronet of a vidame is a circle with four crosses (three visible). Note that coronets of rank did not come into use before the 16th century, and I do not know if there is any evidence for the existence of the vidame's coronet outside of heraldic treatises.
The genealogical information is taken from La Chesnaye-Desbois, Père Anselme and Jougla de Morenas. The institutional details on the vidame are from Achille Luchaire: Manuel des Institutions françaises, période des Capétiens directs; Paris, 1892. The title is also discussed in Du Cange's Glossarium (s.v. advocatus), and in Moréri's Dictionnaire Historique (s.v. vidame; see also the references therein, in particular to a 17th c. treatise on the title of vidame by J. Pillet). Because Saint-Simon held the title, a lot of information is to be found in his Mémoires, text and footnotes (particularly in the fabulous Boislisle edition: see vol. 1 pp. 22-3 and 443, vol. 5. pp.321-4).