The name Normans originally simply refers to Vikings, Germanic people raiding the Eurpean coast from their Scandinavian homes for centuries. As the clergy, their main prey, wrote histories, they got an excessively bad press. Norwegians led by Rollo actually conquered present Normandy, a maritime part of weakened France, and got royal sanctioning by accepting to became a 'vassal' duchy. They soon adapted very well to feudal continental Eurpoean ways, while preserving enough of their military force to become a formidable power. William, one of Rollo's successors, an illegitimate son from a local commoner mother, expertly uses it after consolidating himself as duke to mount an invasion of England. The Bayeux tapestry illustrates various complications, such as the unclear pretext concerning his English rival for the throne, Earl Harold, whose forces were exhausted after defeating a fresh Norwegian invasion from king Harald. William's victory in the battle of Hastings in 1066 made Anglo-Saxon England a semi-gallicized nation.
—KGF Vissers