Yep. Zoarastrians were killing off Romans back in ancient times, too, in the name of their religion. Although a compassionate religion, it wasn't exactly a peaceful religion when its leaders saw it as a unifying tool to incite their populations to war.
Also Armenians. Ever hear the story of St. Vartan?
http://www.armenianchurch.org/heritage/history/vartan/avarayr.html
"Yep. Zoarastrians were killing off Romans back in ancient times, too,.."
A lot of that going around back then.
Romans would systematically crucify tens of thousands of the defeated armies...to crush the spirit of a conquered land.