Ambrose Saint, known as of Milan (c.339–97), Roman church leader and theologian. While bishop of Milan (374–97), he not only led the struggle against the Arian heresy and its political manifestations, but offered new models for preaching, for Scriptural exegesis, and for hymnody. His works also contributed to medieval Latin philosophy. Ambrose’s appropriation of Neoplatonic doctrines was noteworthy in itself, and it worked powerfully on and through Augustine. Ambrose’s commentary on the account of creation in Genesis, his Hexaemeron, preserved for medieval readers many pieces of ancient natural history and even some elements of physical explanation. Perhaps most importantly, Ambrose engaged ancient philosophical ethics in the search for moral lessons that marks his exegesis of Scripture; he also reworked Cicero’s De officiis as a treatise on the virtues and duties of Christian living. M.D.J.