Oh Dave, to burst the bubble of one of your favorite points, the Norman invasion of Britain didn't work because they were of the same Northern stock, but because they seized the land by force. They might as well have been Turks, Arabs or Slavs.
Your other point of having no history shared doesn't apply to Indians, pakistanis or even Omanis does it?
Iberia is different stocks, France is different stocks, Italy, Sicily, Turkey, North Africa, Eastern Europe, the Caucasus, examples are numerous.