Bohemond of Taranto’s campaign in 1107 against the Byzantine Empire has been widely accepted in three major schools of historical thought within the field of crusade studies as a crusade. Yet, this seems oxymoronic on the ground that his intention was not in the completion of pilgrimage to Jerusalem or directly aiding the Crusader states. Considering these issues, this study examines Bohemond’s invasion of the Byzantine Empire in 1107 to determine the range of historical grounds that enabled its identification as a holy crusade, despite the fact that it was a campaign against another fellow Christian community. In order to successfully solve this conundrum, this paper analyzes the historical background of Bohemond and related events leading to 1107, his effort to legitimize this religiously cannibalistic invasion as a crusade, and lastly, contemporary scholarship’s treatment of this historical issue. The observations made in this study will thus provide a bridge between the medieval perception of a holy war and the present imagination of it.