This sourcebook was compiled between August 2020 and April 2021 in order to support the work of students in HIST 2220 – War and Society: The Middle Ages and the Crusades. The primary sources included highlight changes in the techniques and technology of warfare, attitudes towards violence (both in war and outside of it), issues of religious conflict, and the details of participating in various military engagements between the later Roman Empire and the dawn of the Early Modern Era.