Much has been made in recent years about the role of the secretary in the construction of Paul's letters, most notably by Randolph Richards and Ian Elmer. This article focuses on the most famous secretary – Tertius. Through an analysis of what can be learned of Tertius’ identity and his relationship to Paul and to ancient authorial practices in households, it argues that Tertius was probably a slave in the household of one of the Corinthian Christ-followers, whose role was simply to inscribe the letter. His inability to use Paul's signature phrase ἐν κυρίῳ in a Pauline fashion highlights his lack of authorial input. Tertius’ self-initiated greeting in Rom 16.22 probably began life as a marginal comment that was moved early into the letter body.