One day, when I was a child, my father came home with a huge rolled up piece of paper. Some of his relatives were keen genealogists who had researched their family history and drawn a family tree. We opened it out on the dining table and looked for people we recognised. At the bottom we found my father and my grandparents. Nearby we found friends we didn’t know we were related to. Higher up, my father found some famous Rabbis. And, to my amazement, at the top we found King David, and Avraham, and other biblical figures I had learned about in school.