History John D. Hosler is a medieval historian and Professor of Military History at the Command and General Staff College at Fort Leavenworth, Kansas.

[1][2][3] He specializes in the history of warfare in Europe and the Near East during the 11th-13th centuries.

[4] He earned his Ph.D. in history at the University of Delaware in 2005, studying under Professors Daniel F. Callahan and Lawrence G.

[5] He first taught as tenured professor of history at Morgan State University in Baltimore, MD,[6] before taking a position at Fort Leavenworth in 2017.

[7][8][9] He is Co-Editor of the book series "War and Conflict in Premodern Societies", published by ARC Humanities Press, and he sits on the Editorial Board of War Studies Journal.