30. See Vannier, "Creatio" (note 1, above), 68.
18 On Genesis nothing, and that God created freely and not out of necessity. Since such oppo nents ofChristians as Celsus, Porphyry, and Julian the Apostate not infrequently ridiculed elements of the creation story that seemed dubious to them, Christian apologists often had to take up questions in the interpretation of Genesis.26 ln addition, heretical currents stemming from gnosticism, Marcionism, Manicheism, and Priscillianism called for a theological explanation that would oppose any form of dualism and show evil to be not an independent substance but the result of human freedom and demonic activity.
Genesis also played an important role in the catechetical and pastoral instruc tion of the early Church. The reading and interpretation of this book of the Bible soon found a place in the first week of Lent, then in Holy Week, and then during the Easter Vigil.27
Augustine was thus in the line of a lengthy and comprehensive tradition of interpretation. He was familiar with important aspects of the early Christian interpretation of Genesis,28 but the question of the concrete sources on which he drew can be answered with accuracy in only a few instances. At this period cosmological conceptions were generally part of the knowledge acquired by the educated class. It is possible indeed to find parallels in other authors for many of Augustine's concepts, ideas, and images, but it has not been possible to discover a common source text for them. Much in the Hexaemeron literature had made its way into the catechesis of the Church and was handed on orally, so that Augus tine may have gotten to know it in these ways. In any case, he usually altered not only the language but also the content of his sources.
He may also have acquired an indirect knowledge of Greek sources through Latin translations. Nor can we exclude the possibility that he had available a kind of synopsis of various interpretations of the Hexaemeron.29 Basic ideas in the cosmology of Philo of Alexandria may have reached him through the works of Origen, Basil, and Ambrose.30 More important was the influence of Origen himself. Augustine knew his main work, First Principles (De principiis), and the homilies on Genesis 1 and 2 through the Latin translations of Rufinus and Jerome; he may possibly have known Origen's commentary on Genesis, which
26. See S. Ackermann, Christliche Apologetik uncl heidnische Philosophie im Streit um das Alle Testament (Stuttgarter Biblische Beitrage 36; Stuttgart, 1 997) 1 1 81 33; G. Rinaldi (ed.). Biblia gentium (Rome, 1989) 189-227. 27. See A. Ralphs. "Die alttestamentlichen Lektionen der Griechischen Kirche," Nachrichten der koniglichen Gesellschafl der Wissenschaften in Gdttingen. Phil.-hist. Klasse (1915) 26-136; B. Botte. "La choix des lectures de la veillee pascale," Questions liturgiques et pastorales (1952)65-70. 28. See C. Bernardi. "In principio fecit Deus caelum et terram" in San Agostino e le sue fonti (Turin. 1960). 29. See Bouhout, "Pentateuque chez les Peres" (note 19, above). 708. 30. See Vannier, "Creatio" (note 1, above), 68.