Conan III, also known as Conan of Cornouaille and Conan the Fat (Breton: Konan III a Vreizh, and Konan Kerne; c. 1093–1096 – September 17, 1148) was duke of Brittany, from 1112 to his death. He was the son of Duke Alan IV and Ermengarde of Anjou.
On his death-bed in 1148, Conan III disinherited Hoel from succession to the Duchy, stating that he was illegitimate and no son of his. By this surprise move Bertha became his heiress and successor. However, Hoel was to retain the County of Nantes.
- Stephen created Conan's son-in-law Alan 1st Earl of Richmond. Alan rode by the side of Stephen in the Battle of Lincoln.
- The Earldom of Richmond was inherited by Alan's son, and Conan III's grandson Conan IV. It would remain in the Ducal house of Brittany for some time.
- King Stephen of England created Alan 1st Earl of Richmond and 1st Earl of Cornwall
- Bryan, Elizabeth J. (2016). "Matthew Parker and the Middle English Prose Brut". In Rajsic, Jaclyn; Kooper, Erik; Hoche, Dominique (eds.). The Prose Brut and Other Late Medieval Chronicles. York Medieval Press.
- Everard, J. A. (2004). Brittany and the Angevins: Province and Empire 1158–1203. Cambridge University Press.
- Warren, Wilfred Lewis (1977). Henry II. Yale University Press.