Compare and contrast Pope Urban II and his calling to crusade with Pope Innocent III and his call. Consider: How many crusades? What did each pope cite as his justification for the crusades? Which spiritual benefits did each offer? What may account for any differences?

Urban II's First Crusade and Innocent III's Fourth Crusade were markedly different in tone and scope. In theory, both had similar aims--they sought to recapture the Holy Land--but the nuances of Urban II's call were very different from those of Innocent III's, for which reason Urban II was able to stir up huge support across much of Europe, whereas Innocent III largely failed to garner any support except in France.
There is no direct transcript of what Urban II said in calling for the First Crusade, but we do know that he preached the crusade with the goal of liberating the Holy Land from the "wicked" Saracens. He also promised that crusaders would be able to earn forgiveness for their sins through their efforts. Buoyed by an apocalyptic fervor driven by a general feeling that the millennium might mean the return of Christ, huge numbers of people joined Urban II's crusade to Jerusalem.
Innocent III, meanwhile, is generally regarded as something of a megalomaniac pope whose key goal was to expand the territories governed directly by the Papacy. Jerusalem had been lost in the Second Crusade; Innocent took as one of his main goals the recapture of Jerusalem and preached this when he ascended to the Papacy. However, his motives were doubted; in England, in particular, he gained little support, as he had been attempting to extend unpopular taxes to the country and was viewed with suspicion. The aura of true faith around the First Crusade was not extant in the case of the Fourth Crusaders, and ultimately this became a mission of greed that went nowhere near Jerusalem and instead resulted in the sack of Constantinople by Crusaders desirous of physical spoils. Innocent III was also an enthusiastic condemner of heresy and drove crusades against the Albigensians and Cathars in France, which, in actuality, also resulted in significant violence towards Jews.