Isembert de Châtelaillon

Who is 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 in Charente-Maritime, a territory which covered the area between the Sèvre river in the north and the Charente river 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.

Isembert was a descendant of the powerful Isembert I of Châtelaillon who became prosperous through wine and salt trade, and sponsored the development of monasteries. Isembert I built the monastery of Ile d'Aix in 814, which was later invaded by the Normans and became one of their strongholds.

Isembert was also the son of Eble II of Châtelaillon, who was known for his depredation of local monasteries and was twice excomunicated as a consequence.