This article identifies a double allusion to the tragic characters of Phaedra and Eriphyle in Amm. Marc. 14.1.3 and considers its possible meanings. In combination, these allusions evoke the double nature of the story of Eriphyle, therefore functioning as a reference to the double nature of Caesar Gallus’ depiction in Ammianus. The double allusion consequently forms part of Ammianus’ tragic style throughout Book 14. Having identified the presence of this double allusion, the article illuminates its possible meaning by connecting Ammianus’ passage to the Virgilian rewriting of the description of Eriphyle in Homer.