This is just an idea I had, I'm not saying I believe it, I just thought it made an interesting thought experiment. When you look at the number of countries that were involved in the crusades, could we consider them a 'world war'?

I'm no expert, but I think the following areas were all involved in some way: Anatolia, Asia Minor, Austria, Baghdad, Bulgaria, Byzantine Empire, Cyprus, Dalmatia, England, France, Germany, Greece, Holy Land, Hungary, Italy, Low Countries, Mongolia, Norway, Persia, Portugal, Prussia, Russia, Sicily, Spain, Syria, Tunisia and Turkey. I know some of these area may overlap, and there is a mix of medieval and modern names, but I'm not great at Geography!

Probably the main objection is that the crusades were not 'a' war, but a series of wars.

Any thoughts?