In 806 AD, Holy Roman Emperor Charlemagne attempted to divide his empire among his three heirs (Charles the Younger, Pepin of Italy,
not to be confused with Pepin the Hunchback, and Louis the Pious) in, roughly, the above map's configuration. However, around three years before the death of the great emperor, Charles and Pepin died young. Louis the Pious ended up inheriting the empire in one piece, delaying its division until his death.
IOTL, the empire was divided in 843 in a roughly "west-middle-east" configuration.
But, suppose that Charles and Pepin live longer, and also sire heirs. The empire is divided as Charlemagne willed in 806.
How does this affect the history of Western Europe? Assuming that the mainframe of this territorial configuration ("north-southwest-southeast") is maintained for the coming centuries, what of it?
It seems to me that "North Francia" would be well-positioned to deal with England and the Vikings, for example.