The first complete set of Latin commentaries on the Pauline epistles (sans Hebrews), composed by an unknown Roman presbyter and issued anonymously in multiple recensions under the pontificate of Damasus (366–382), had the great fortune to be attributed to Ambrose by most of the manuscript tradition. Included in the first printed editions of Ambrose’s works, they were read and mined by both Protestant and Catholic theologians for polemical and pastoral purposes. One reformer who made extensive use of these commentaries on Paul, was Heinrich Bullinger, who succeeded Zwingli as Zürich's chief pastor in 1531. By 1537 Bullinger published a complete series of commentaries on Paul, which extensively quote—and laud—Ambrosiaster’s works on Paul alongside those of other patristic exegetes as well as humanistic biblical scholars. One of the major emphases in Ambrosiaster’s commentaries is a sharp historical focus on Paul’s opponents, the so-called pseudoapostoli; alongside this is the unknown exegete’s insistence upon the church having a viable system of penitence able to re-incorporate erring members. These threads of Ambrosiaster’s Paul-commentaries appear to have resonated with Bullinger, who devoted great effort toward achieving a working concord with other Protestant reformers (a successful effort with Geneva and an ultimately unsuccessful attempt at dialogue with Lutherans). In this paper I will begin the work of evaluating the impact of Ambrosiaster’s commentaries on Bullinger through an analysis of how the latter’s treatment of the pseudoapostles of Second Corinthians reflects the comments of Ambrosiaster.