When Arabers occupied Spain, there were a lot of Jews there. At that time, Arabers and Jews were not enemies. Jew were (and are) pretty good business men. Germans invited many Jews to come over and however asked Jews to buy German names. Rich Jews got better names and poor Jews got bad names. Most Jews got some German words as names, but not German names. Like Einstein means "one stone". No native German has this name. Hitler could find many Jews out simply from their names.