This interview reveals the fascinating story behind the start of the Crusades. The Eastern Orthodox had just split off from the Catholic Church. But they were mauled by the Muslims and looked to the Catholics they just rejected for help:
Addendum:
Fred provided these images in connection with his comment below:
The First Crusade was the response of the Christian world to the expansion of Islam. The Byzantine need for military support coincided with an increase in the willingness of the western European warrior class to accept papal military command.
It is quite likely that personal piety was a major factor for many crusaders. The crusade was led by some of the most powerful nobles of France.
I am reminded of the crusades by the current war in Iran.
BTW, my Dad was a Freemason and a member of the Knights Templar.
Armenia seems to have been in the crosshairs of some of history’s greatest tragedies, Fred. I was not familiar with this background of the first crusade.
Also, I had no idea your Dad would have been part of the Knights Templar!