https://www.youtube.com/watch?v=I_To-cV94Bo
This has been making rounds on Facebook and after some research I found that Dr. Warner is a mathematician and not a historian. I am unfamiliar with his work, and was wondering if he is being historically accurate, or simply pandering to conservatives looking to find something against Obama's recent comments regarding the Crusades.
hi! not discouraging other responses, but this recent post is related to the video you've posted:
you may be interested in a few more posts on the Crusades