Their outfits are also the standard costume worn by the popular mystery gods Orpheus and Mithras in late antiquity. Concerning their dress, see Thomas Mathews, The Clash of Gods: A Reinterpretation of Early Christian Art (Princeton, NJ: Princeton Univ. Press, 1993), p. 84. Here Mathews also makes this point about Orpheus. Mathews also cites Franz Cumont’s analysis of their dress as replicating that of captive barbarians. See Cumont, “L’adoration des Mages et l’art triumphal de Rome,” Memorie della Pontificia Accademia Roma di Archeologia 3 (1932–1933), pp. 81–105. On Orpheus’s role in Christian art, see Robin Jensen, Understanding Early Christian Art (London and New York: Routledge, 2000); and M. Charles Murray, Rebirth and Afterlife: A Study of the Transmutation of Some Pagan Images in Early Christian Art (Oxford: BAR, 1981), pp. 37–63. On the comparison with Mithras, see Leroy A. Campbell, Mithraic Iconography and Ideology (Leiden: Brill, 1968).