Did Rollo From Vikings Really Exist?
Many characters of History channel's "Vikings" are either entirely fictional or loosely based on historical or mythical figures (via World History Encyclopedia). Rollo, portrayed by Clive Standen, is one of those based on an actual historical figure of the same name. In the series, he is the brother of Ragnar Lodbrok, one of the show's lead characters, and depicted as being constantly at odds with the protagonist for much of the series (via Express).
His ambition leads him to betray his brother on several occasions before finally abandoning him and his people for the Franks. While the real Rollo had no connection to Ragnar, nor was he alive when many of the events featured in the series took place, he was indeed a pagan who ultimately turned to the southern Christians for power. This path, like in the show, led him to become the founder of one of medieval Western Europe's most important regions, Normandy.
Rollo was the first Duke of Normandy, and a direct descendant of William the Conqueror
Rollo formally became the first Duke of Normandy almost three decades after he helped lead an army into northern France against Charles III in 885 A.D. (via Britannica). The Frankish king was able to fend off the former's attempted capture of Paris and in the immediate aftermath negotiated with the invader; Rollo would keep the lands he had already taken in exchange for his protection of Francia and, for formal recognition of the Duchy, acceptance of being baptized in 911 A.D. (via The Dockyards).
While her actual existence is debatable, he is also believed to have married the French princess Gisela at this time as well (like in the show). Though Charles himself was overthrown just a few years later, the new Duchy remained and by the following century was still a powerful region. In 1066 A.D. Rollo's descendant William managed to successfully lead an invasion of England, taking its crown for himself (via Vikingeskibs Museet). His bloodline lost its control of Normandy in the 1200s, but through William, Rollo's lineage went on to forever shape monarchy in the British isles.