Geoffrey I of Brittany was a notable figure in the medieval period, serving as the Duke of Brittany from 990 until his death in 1008. He was the son of Conan I, Duke of Brittany and Ermengarde of Anjou. Geoffrey's reign was marked by efforts to strengthen the duchy's independence and consolidate power within the region. Geoffrey I is also known for his marriage to Hawise of Rennes, which helped to solidify alliances with neighboring territories. His legacy continued through his children, particularly Geoffrey II, who succeeded him as duke, ensuring the continuation of the House of Rennes.