Vikings

Rollo was based on a real Viking called Hrolf (latinized as Rollo) who went on to conquer parts of France. Those parts are now known as Normandy: "Land of the Norsemen". Hrolf was the ancestor of William the Conqueror. Actually being William's Great-Great-Great Grandfather.

Rollo was originally written to be Ragnar's cousin.

The women in the opening credits are supposed to be the 9 daughters of Rán, the personifications of the waves. The title sequence is supposed to show the separation of a viking from the living, with the ornaments of his life (gold and weapons) floating down around him. During the shot of the rolling thunder there is a single frame showing Hel Lokisdottir: the goddess of death.