Some scholars question whether there really was a formal catechetical school as early as the second century, rather than just independent teachers; see Roelof van den Broek, “The Christian ‘School’ of Alexandria in the Second and Third Centuries,” in Centres of Learning: Learning and Location in Pre-Modern Europe and the Near East, ed. J.W. Drijvers and A.A. MacDonald (Leiden: Brill, 1995). The preponderance of evidence, however, strongly indicates that there was one; see W.H.C. Frend, The Rise of Christianity (Philadelphia: Fortress, 1984), p. 286; Eusebius’ Ecclesiastical History (Grand Rapids: Baker, 1955), pp. 190–191, 217–255; Schaff and Wace, eds., The Nicene and Post-Nicene Fathers, 2nd ser., vol. 1 (Grand Rapids: Eerdmans, 1952), pp. 224–226, 249–281; and G. Bardy, “Aux origines de l’ecole d’Alexandrie,” Reserches de Science Religieuse 27 (1937), pp. 65–90.