A distinctive feature of the biographies of Suetonius is his methodical and detailed description of the physical appearances of the emperors. This feature was adopted by two fourth-century Latin writers, Ammianus Marcellinus and the anonymous author of the Historia Augusta. This study will explore how ancient theories of the relationship between appearance and character intersect with the physical descriptions of emperors the authors provide. These authors reveal themselves to be engaged with contemporary approaches to the question without being bound by (...) any one theory, and thus presuppose a readership for whom physiognomic questions were both interesting and debatable. The approaches of the authors to this minor feature in their work also offer broader insight into their biographical style and purpose. (shrink)