> There was an invasion of England in 1066 by William the Bastard, Duke of Normandy, which ended up with King William I of England. Subsequent monarchs of England/bits of France were no longer Normans per se. At least one variety of a French language at the time was introduced, wholesale, and became the court language of England.

There was more than that. For a while, England was a backwater of the Angevin empire and kings of England were native French speakers for quite a long time.