For a similar amulet, cf. The Erlenmeyer Collection of Ancient Near Eastern Stamp Seals and Amulets, Christie's London, 6 June 1989, lot 322. This type of bifrons bull is considered by Dr A. Roes (Greek Geometric Art, its Symbolism and Origins, Oxford, 1933, p. 93ff.) to be a solar symbol as well as having magical connotations. The bull, Anu, was worshipped by the Sumerians as a sky god. Also see a lapis lazuli parallel from the Royal Cemetery at Ur (C. L. Wooley, Ur Excavations, London and Philadelphia, II, pl. 142).