There were eight "official" Crusades in the Middle Ages. Mr. Michael Davies goes into detail on the remaining seven: the inconclusive second; hopeful but ultimately problematic third; disastrous fourth, which involved the excommunication of the crusading army and sack of Constantinople; and the basically unsuccessful fifth through eighth enterprises. One figure who stands out in the later Crusades is, of course, St. Louis IX of France. Taken from: Crusading, the Crusader & the Christian Order - 2002 VonHildebrand Institute