Vermandois, a French countship composed originally of the two burgraviates (chatellenies) of St Quentin (Aisne) and Peronne (Somme). Herbert I., the earliest of its hereditary counts, was descended in direct male line from the emperor Charlemagne, and was killed in 902 by an assassin in the pay of Baldwin II., count of Flanders. His son, Herbert II. (902943), a man absolutely devoid of scruples, considerably increased the territorial power of the house of Vermandois, and kept the lawful king of France, the unlucky Charles the Simple, prisoner for six years. His successors, Albert I., Herbert III., Albert II., Otto and Herbert IV., were unimportant. In 1077 the last male of the first house of Vermandois, Herbert IV., received the countship of Valois in right of his wife. He died soon afterwards, leaving his inheritance to his daughter Adela, whose first husband was Hugh the Great, the brother of king Philip I. Hugh was one of the leaders of the first crusade, and died in 1102 at Tarsus in Cilicia. The eldest son of Hugh and Adela was count Raoul (Rudolph) I. (c. 1120-1152), who married Alix of Guyenne, sister of the queen, Eleanor, and had by her three children: Raoul (Rudolph) II., the Leper (count from 1152-67); Isabelle, who possessed from 1167 to 1183 the countships of Vermandois, Valois and Amiens conjointly with her husband, Philip of Alsace, count of Flanders; and Eleanor. By the terms of a treaty concluded in 1185 with the king, Philip Augustus, the count of Flanders kept the countship of Vermandois until his death, in 1191. At this date a new arrangement gave Eleanor (d. 1213) a life interest in the eastern part of Vermandois, together with the title of countess of St Quentin, and the king entered immediately into possession of Peronne and its dependencies.
See Anselme, Histoire genealogique de la maison royale de France (1726), i. 48-51 and 531-34; Colliette, Memoires pour l'histoire du Vermandois (1771-72). (A. Lo.)