Rollo (died between 928 and 933) was a Viking who, as Count of Rouen, became the first ruler of Normandy, today a region in northern France.
He emerged as the outstanding warrior among the Norsemen who had secured a permanent foothold on Frankish soil in the valley of the lower Seine.
After the Siege of Chartres in 911, Charles the Simple, the king of West Francia, granted them lands between the mouth of the Seine and what is now Rouen in exchange for Rollo agreeing to end his brigandage, swearing allegiance to him, religious conversion and a pledge to defend the Seine's estuary from Viking raiders.
The siege of Chartres
The siege of Chartres was part of the Viking incursions in France.
In 911, the Viking Rollo led a siege on the city of Chartres, which had previously been raided and burned by Vikings in 858. The siege resulted in the defeat of the Viking forces.
After negotiations with Charles the Simple, he was then granted the Duchy of Normandy in exchange for loyalty to the kingdom of West Francia.
The Treaty of Saint-Clair-sur-Epte
The treaty of Saint-Clair-sur-Epte was agreed on between Rollo and Charles the Simple, who met personally to discuss the terms.
Rollo was granted the land around the mouth of the Seine and Rouen. This marked the establishment of the Duchy of Normandy.
In exchange for this land, Rollo promised his loyalty to West Francia, religious conversion to Christianity, and a promise to defend the Seine's estuary from other viking raiders.