Rollo was a Viking warrior who in the late 9th and early 10th Centuries carved out the province of Normandy in what is now northwest France.

He was born about 860. He left his native Scandinavia, along with a large handful of fellow warriors, in the early 10th Century, raiding England and Scotland, and then targeted Flanders and Frankish territory, besieging Paris in 885 and then Chartres about 911. Rollo made so much trouble that he eventually got Charles III of France to give him land in return for stopping the attacks. The Treaty of Saint-Clair-sur-Epte guaranteed Rollo and his men some land in what was then the province of Nuestria. The promise that Rollo made, in addition to ceasing fighting, was to convert to Christianity. In return, Charles gave his daughter Gisela in marriage to Rollo.

Rollo and his men were from Norway or Denmark. (Scholars disagree on which.) The locals referred to them as Northmen, and this was how the land of Normandy got its name. Its capital was Rouen.

As well, Rollo was the subject of a handful of stories, some of which were legendary. He was also known as Robert or Rou (as in the subject of Roman de Rou, a 12th-Century chronicle by the Norman poet Wace). He was sometimes referred to as Rollo the Walker or Rollo the Gangler because he said to be so tall that when he sat on a horse, his feet dragged on the ground.

Rollo died in the early 930s, and his son William I Longsword succeeded him as the Norman leader.