There has always been controversy surrounding Frida's father's religious roots. For years biographers have claimed that Carl Wilhelm Kahlo was of Hungarian Jewish decent. A recently published German book: "Fridas Vater: Der Fotograf Guillermo Kahlo" (Frida's Father: The Photographer Guillermo Kahlo) by Gaby Franger and Rainer Huhle, disputes that claim. Their research of Wilhelm's roots as far back as the 16th century indicates that he was born in Pforzheim, Germany, not Hungary, and comes from a long line of German Protestants (Lutherans). Researchers now believe that his "Jewish roots" were simply contrived by Frida to disassociate herself from the German Nazis during WWII.