E. D. Van Buren, Symbols of the Gods in Mesopotamian Art (Rome: Pontifical Inst., 1945), p. 22. The significance and function of the sacred tree has given rise to more discussions than almost any other symbolic element; cf. the comprehensive study by H. Danthine, Le palmier-dattier et les arbres sacrés dans l’iconographie de l’Asie occidentale ancienne (Paris: Geuthner, 1937), pp. 210–213.