A unique treasure has been kept in Uppsala University Library in Sweden since the 17th century: the Gothic Codex Argenteus. The aim of this chapter is to examine Göran Tunström's novel Tjuven (1986; The Thief) about a fictive theft of the codex, and its use of Late Antique writing techniques and texts, both real and fictive, from the perspective of cultural memory studies with a particular interest in media studies, guided by Astrid Erll's Memory in Culture (2011), based on semiotic models. The different functions of the codex, the novel and the library, respectively, are discussed as memory media. This is done in order to inquire into the identity of the thief and to demonstrate the importance of media for the plot. Late Antique writing techniques and intertexts, together with the role of the historian Procopius of Caesarea (early 6th century) in the novel are explored. The motif of writing on skin in The Thief, particularly the writing of history on female skin, is examined. By focusing on how Late Antiquity is inscribed in Tunström’s novel, it is demonstrated how the obsession with writing is vital for all these aspects of the mediation of cultural memory.