The Rover name dates back from when John Kemp Starley produced a tricycle upon which he believed the owner could 'rove' anywhere. Shortly afterwards JKS developed the 'safety' bicycle- i.e. chain drive to the rear wheels, and both wheels approx. the same size. The name was so appropriate that the company name was changed to the Rover Cycle Company (or similar).
The name of the company went through a few changes, but always the word Rover predominated, so the cycles and later motorcycles and a bit later cars all bear the brand Rover.
The emblem as fitted to the bikes was shield-shaped, and some of the early cars had a shield shaped radiator, Perhaps the shield had an influence, but certainly post WW1, the name Rover started to be associated with the likes of Eric the Red and his compatriots, renowned as being great rovers. In the 1920's there were quite a few stories, often as boy's books, of the exploits of Viking rovers.
I think it has been lost to history who suggested the conjunction of the Rover product name with Vikings, but once it happened it stuck.
Dane.