His research and teaching focus on religion, violence, nostalgia, and apocalypse (in various combinations), whether manifested in the Middle Ages or modern world. This includes events and ideas such as the Crusades, the so-called “Terrors of the Year 1000,” and medieval religious and political life more generally. He also has presented and published on modern medievalism, such as recent white supremacist appropriations of the Middle Ages and pop culture phenomena like Game of Thrones or video games.

He has published several books and numerous articles. He also has presented at dozens of national and international conferences and has given talks at Harvard, Princeton, Georgetown, the University of California-Berkeley, the University of Wisconsin-Madison, the University of Virginia, the University of Minnesota, the University of Tennessee-Knoxville, the University of Kent, and Nottingham Trent University. In 2010, he was a visiting researcher at Westfälische Wilhelms Üniversität-Münster, and in 2023-24, he’ll be the Donald J. Bullough Fellow in Mediaeval History at the University of St. Andrews, UK.

His public writing has appeared in such places as The Washington Post, Time, Forbes, and The Daily Beast. Interviews with him have aired locally, nationally, and internationally. He was a columnist for Forbes (until 2019), and also was a columnist for Smithsonian Magazine (until 2021).

His book, co-authored with David M. Perry, is out now: The Bright Ages: A New History of Medieval Europe (Harper Books, 2021).

His new book will also be with David M. Perry and is entitled Oathbreakers: The Carolingian Civil War and the Collapse of an Empire in the Middle Ages (Harper Books, 2024).

See his academic CV.