The Vitae Patrum is based on extensive research by Rosweyde into all the available literature he could find on the early desert monastics. Hippolyte Delehaye described the work as "the epic of the origins of monasticism in Egypt and Syria, an epic unsurpassed in interest and grandeur." In the thirteenth century, a version of Vitae Patrum had been translated into Latin. It was such a popular book that numerous versions and editions were published, with extensive changes and variations in the stories. Rosweyde based his book on twenty-three different versions of those earlier books, studying, dating, and classifying all the different versions and changes.