Isembert de Châtelaillon

Isembert de Châtelaillon, or Isembard de Castrum Allionis, also Isembert the Last, also spelled Isambert, was a French nobleman and the master of the city of Châtelaillon, Charente-Maritime, a territory which covered the area between the Sèvre in the north and the Charente in the south and included Ré Island and Aix Island but not Oléron Island, in the early 12th century. Isambert, like all the Lords of Châtelaillon was a vassal of the Duke of Aquitaine and Count of Poitou. The Châtelaillon lineage is thought to have been founded by Alon, who gave his name to Castrum Alionensis.