First Crusade

The first to set out, in the spring of 1096, were bands led by Peter the Hermit and Walter Sans Avoir; other unofficial companies, among them that of Emicho, attacked the Jews of Speyer and Worms in May and destroyed the Jewish community of Mainz. Alexios ferried Peter's followers across the Bosporus, where the Turks of Kilij Arslan destroyed them at Civetot in October. The princes' armies left around the appointed date in August 1096 by different routes: Godfrey of Bouillon with the Lorrainers through Hungary, Raymond of Toulouse and the legate Adhemar along the Dalmatian coast, Bohemond of Taranto and his Normans across the Adriatic, followed by the northern French and Flemish under Robert of Normandy, Robert of Flanders and Stephen of Blois. Between November 1096 and April 1097 they gathered at Constantinople, where most leaders swore to restore to the emperor the former imperial lands they took from the Turks. Steven Runciman estimated their numbers at 60,000 to 100,000 people, non-combatants included.

In June 1097 Nicaea, the capital of the Sultanate of Rum, surrendered to the Byzantines after a joint siege; on 1 July the crusaders defeated Kilij Arslan at Dorylaeum and then crossed Anatolia in the summer heat, losing many men and horses. Baldwin of Boulogne broke away and in March 1098 became count of Edessa, founding the first crusader state. Antioch, besieged from October 1097, fell in early June 1098, when an Armenian named Firuz, who commanded a section of the walls, let Bohemond's men in; besieged in turn by Kerbogha of Mosul, the crusaders broke out on 28 June, after the discovery of what was claimed to be the Holy Lance. Quarrels over Antioch, which Bohemond kept instead of handing it to Alexios, delayed the march, and only in June 1099 did a much reduced army — by Raymond of Aguilers' count some 1,200–1,300 knights and about 12,000 foot soldiers — reach Jerusalem, which the Fatimids had taken from the Turks the year before. With timber brought by Genoese sailors the crusaders built siege towers, and on 15 July they broke into the city; Muslims and Jews were slaughtered, although historians debate the scale of the massacre described by the chroniclers. Godfrey was chosen ruler with the title of Advocate of the Holy Sepulchre, and on 12 August he defeated a Fatimid army at Ascalon. Urban II had died on 29 July, before the news reached Rome.

The crusade created four Latin states — Edessa, Antioch, Jerusalem and later Tripoli — and a model of armed pilgrimage that would be repeated for two centuries; it also deepened the mistrust between Latins and Greeks.