Hawise of Rennes was a notable figure in medieval Brittany, born around 1070. She was the daughter of Duke Alan IV of Brittany and Hawise of Normandy. Hawise became the wife of Duke Conan IV of Brittany, strengthening the ties between noble families in the region. As a duchess, Hawise played a significant role in the political landscape of Brittany. She was the mother of several children, including Duke Pierre de Bretagne, who succeeded Conan IV. Her lineage contributed to the ongoing influence of the House of Rennes in the region's history.