While Ambrose of Milan was a major actor on the ecclesiastical and political stage of late antiquity, he was also a devoted catechist and theologian. This chapter focuses on how Ambrose trained the spiritual senses of catechumens throughout Lenten and Eastern catechesis. In Lenten sermons on the patriarchs, Ambrose focused on baptism as a death to physical ways of seeing. In Holy Week sermons (On the Hexameron and Explanatio symboli), he sought to restructure catechetical knowledge by offering pro-Nicene accounts of God and creation. In mystagogical sermons (De mysteriis and De sacramentis), he gave neophytes instruction on how to perceive the spiritual meaning of the Christian rites.