SHEM-TOB] DE (d. 1305), Jewish scholar, was born in Leon (Spain) in the middle of the 13th century and died at Arevalo. His fame is due to his authorship of the most influential Kabbalist work, the Zohar (see Kabbala), which was attributed to Simon b. Yohai, a Rabbi of the 2nd century. In modern times the discovery of the modernity of the Zohar has led to injustice to the author. Moses de Leon undoubtedly used old materials and out of them constructed a work of genius. The discredit into which he fell was due partly to the unedifying incidents of his personal career. He led a wandering life, and was more or less of an adventurer. But as to the greatness of his work, the profundity of his philosophy and the brilliance of his religious idealism, there can be no question.
See Graetz, History of the Jews, vol. iv. ch. i.; Geiger, Leon de Modena. (I. A.)