However, from 885 to 886, Odo of Paris (Eudes de Paris) succeeded in defending Paris against Viking raiders. His military success allowed him to replace the Carolingians. In 911, a band of Viking warriors attempted to siege Chartres but was defeated by Robert I of France. Robert's victory later paved way for Rollo's baptism and settlement in Normandy. Rollo reached an agreement with Charles the Simple to sign the Treaty of Saint-Clair-sur-Epte, under which Charles gave Rouen and the area of present-day Upper Normandy to Rollo, establishing the Duchy of Normandy. In exchange, Rollo pledged vassalage to Charles in 940, agreed to be baptised, and vowed to guard the estuaries of the Seine from further Viking attacks. During Rollo's baptism Robert I of France stood as his godfather. The Duchy of Normandy also annexed further areas in Northern France, expanding the territory which was originally negotiated.