Scholars believe that the concept of a tree of life with different spheres encompassing aspects of reality traces its origins back to Assyria in the 9th century BC. The Assyrians also assigned values and specific numbers to their deities similar to those used by the later Jewish Kabbalah. The beginnings of the Jewish Kabbalah are traced back by scholars to the Medieval Age, originating in the "Book of Bahir" and the "Book of Zohar". However, the first historical instance of the modern diagram appeared centuries later in the cover of the Latin translation of "Gates of Light" in the year 1516. Scholars have traced the origin of the art in the "Porta Lucis" cover to Johann Reuchlin.