For those curious, I would like to recommend the book I am currently reading: The First Crusade: A New History by Thomas Asbridge. Mr. Asbridge is a professor of medieval history at the University of London. I’m only about a third of the way through it, but so far, the book is very insightful on just how the First Crusade started and how the crusading fire swept through Europe. Here’s a link if you want to take a look or purchase it. FYI, this is for your benefit, I get nothing from Amazon.