In the 1960s, British historian Jonathan Riley-Smith first began studying the knightly orders of the Middle Ages that formed after the First Crusade. By the late 1970s, he had begun writing books from a "revisionist" point of view, challenging the common belief that the Crusades were motivated by fanaticism, and were designed to plunder the Holy Lands. To an extent, Riley-Smith's 1986 book The First Crusade and the Idea of Crusading overturned this previously held view.
Riley-Smith came to his conclusions after studying handwritten documents held in churches across Western Europe, in which Crusaders explained their personal reasons for heading out on the "holy war." He then pioneered the use of computer spreadsheets to cross-reference data on individual Crusaders and their families, which allowed him to paint a much more complete picture than had been seen previously. He came to the conclusion that most Crusaders were actually motivated by spiritual devotion and a genuine desire to atone for past sins.