England, What England?

The Mid-West, North, & South-West of the country we now call England is undoubtedly Celtic. The country shouldn't be called England as the Germanics who landed there and who lent it their name after the heptarchie became united was conquered by the Vikings of the mouth of the Seine whom we call 'Normans', so the name 'England' should have disappeared with the conquest! Then there was the Angevin empire of which England was but a minor party, and the Plantagenet French wh ruled the country until the Welsh Tudors took over at the end of the 15th century; England, what England?