MAP 10.1 The First Crusade, 1096–1099
The First Crusade was a major military undertaking that required organization, movement over both land and sea, and enormous resources. Four main groups were responsible for the conquest of Jerusalem. One began at Cologne, in northern Germany; a second group started out from Blois, in France; the third originated just to the west of Provence; and the fourth launched ships from Brindisi, at the heel of Italy. All joined up at Constantinople, where their leaders negotiated with Alexius Comnenus for help and supplies in return for a pledge of vassalage to the emperor.