The earlier view, sometimes still repeated, that these christograms emerged in the post-Constantian period—and that the chi-rho was the earliest and the tau-rho developed from it—are now all shown to be erroneous. These influential claims were made by M. Sulzberger, “Le symbole de la Croix et les monogrammes de Jésus chez les premiers Chrétiens,” Byzantion 2 (1925), pp. 337–448. Also shown to be incorrect is Sulzberger’s claim that there was no Christian use of the cross-symbol, no christogram, and no representation of Jesus’ crucifixion before the fourth century C.E. (p. 371). Among works that perpetuate Sulzberger’s views long after they were shown incorrect, see G.F. Snyder, Ante Pacem: Archaeological Evidence of Church Life Before Constantine (Macon, GA: Mercer Univ. Press, 1985; 2nd ed. 2003).