Have you evidence that any of Mendelssohns contemporaries regarded him as Jewish? The notion of Jewishness being 'genetically' defined is a 20th century one that should be left behind with the vile political movements that accompanied it. What evidence have you that mine is a minority view? A visit to an Israeli city is enough to show that Jewishness cannot possibly be racially defined except for political purposes - every racial group is present from Nordic to African, all Jewish! In Mendelssohn's time there were simply three religious communities in Germany and folks moved, like the Mendelssohns, from one to another. Don't perpetuate Nazism.