The Viking leader who founded the Norman settlement after receiving land from the Frankish king in 911 was Rollo.
The Treaty of Saint-Clair-sur-Epte was made between Rollo and King Charles the Simple of West Francia. In exchange for baptism, loyalty and protection of the Seine region, Rollo received territory that became the core of Normandy. The arrangement helped create a powerful frontier principality rather than ending Scandinavian influence in the area immediately.
Later Norman rulers traced their dynasty to Rollo, including William the Conqueror, who invaded England in 1066. Medieval sources disagree about Rollo’s exact origins and early career, and some details come from traditions written long after his lifetime. He is therefore a well-attested founder of Normandy, but not every story about his youth can be treated as certain.