Dr. John Rao explains that the monks of Cluny aided the maturation process enormously, teaching rough soldiers how they could use their military skills for acceptable purposes. The Pilgrimage to Compostella became a training ground for Crusaders. Also, Moslem Sufi Brotherhoods, some of them very militant, taught how spiritual and military activity could go together. Taken from: Crusading, the Crusader & the Christian Order - 2002 VonHildebrand Institute