Rollo (born c. 860—died c. 932) was a Scandinavian rover who founded the duchy of Normandy.
According to later Scandinavian sagas, Rollo, making himself independent of King Harald I of Norway, sailed off to raid Scotland, England, Flanders, and France on pirating expeditions. Early in the 10th century, Rollo’s Danish army attacked France, and he established himself in an area along the Seine River. Charles III the Simple of France held off his siege of Paris, defeated him near Chartres, and negotiated the treaty of Saint-Clair-sur-Epte, giving him the part of Neustria that came to be called Normandy; Rollo in return agreed to end his brigandage. He gave his son, William I Longsword, governance of the dukedom (927) before his death. Rollo was baptized in 912 but is said to have died a pagan.