Bertha, Duchess of Brittany

Bertha of Cornouaille ( 1125–56), also known as Bertha of Brittany , was the Duchess of Brittany and the Dowager Countess of Richmond from 1148 until her death. Bertha was the elder daughter of Conan III of Brittany by Maude, the illegitimate daughter of King Henry I of England. She was the last member of the Breton house of Cornouaille to reign over Brittany.

Life Bertha was the daughter of Duke Conan III of Brittany. She married the son of Stephen of Treguier, Alan the Black, and she lived in England with Alan until his death in 1146. Alan would eventually become Earl of Richmond. On his deathbed, Conan III renounced Bertha's brother Hoel as heir and designated Bertha as his heiress, Duchess of Brittany.

Family In her first marriage, by 1138, Bertha was married to Alan the Black.

Bertha and Alan had three children: Conan IV, b. 1138, their son and heir, as Duke of Brittany and Earl of Richmond Constance, who married Alan III, Viscount of Rohan Enoguen, abbess of St. Sulpice

Bertha married her second husband, Odo, Viscount of Porhoet, in about 1148. Bertha and Odo had three children: Geoffroy Adelaide (died in 1220), Abbess of Fontevrault, mistress of Henry II, King of England Alix

Succession Bertha died between 1158 and 1164, and with her death the ducal throne passed to her son Conan.