Mattias Gassman is Assistant Professor in the Hamilton School for Classical and Civic Education. A Classicist and scholar of the late antique world, he was previously a postdoctoral researcher at the University of Oxford and the University of St Andrews. His research centers on a core theme in the history of Western culture: the transformation of the Roman Empire by Christianity. He has published two books with Oxford University Press. The first (Worshippers of the Gods: Debating Paganism in the Fourth-Century Roman West, 2020) shows how Christians and pagans rethought traditional Roman religion from the last empire-wide persecution of Christians (303–313) to the end of public funding for the Roman civic cults in the 380s. In the second (Citizens of the Earth: Pagans and Their Gods in Augustine’s North Africa, 2025), he provides the first comprehensive account of the ideas on Roman religion advanced by the most influential of all late Latin writers: Augustine, bishop of Hippo Regius (354–430). Together, the two books offer a wide-ranging new account of late antique religious theories and the social and cultural context in which they took shape, and test modern organizing concepts such as “secularity,” “paganism,” “identity,” and “religion” against the ideas actually articulated by ancient thinkers.

Gassman has also co-authored a book, aimed at a general audience, on fourth- and fifth-century theological controversy. Written with Brendan Wolfe and Oliver Langworthy (University of St Andrews), Arianism Revisited: An Introduction to Non-Nicene Theologies appeared from Fortress Press in June 2025. In addition, he has published nearly two dozen articles in venues such as Journal of Early Christian Studies, Journal of Late Antiquity, and The Journal of Roman Studies.