Kerbogha was Atabeg of Mosul during the First Crusade and was renowned as a soldier. In 1098, when he heard that the Crusaders had besieged Antioch, he gathered his troops and marched to relieve the city. By the time he arrived, on July 7, the Crusaders had been in possession of the city for four days. They were not able to restock the city before Kerbogha, in turn, was besieging the Crusaders in the city.
During the siege, Peter the Hermit was sent as emissary to Kerbogha by the Christian princes in the city, to suggest that the parties settle all differences by duel. Presumably feeling his position secure, Kerbogha did not see this course of action as being in his interest and he declined.
During the siege, inside the city, Peter Bartholomew claimed to have discovered the Holy Lance through a vision. This discovery re-energized the Christian army. At the same time, disagreements and infighting broke out within the Atabeg's army. When Bohemond, the leader of the Christian army decided to attack, Kerbogha was taken by surprise because the information he had received was of a weak, disorganized Christian army. Instead, he found himself facing a motivated, unified Christian army while his own force was divided. He had to retreat, and returned to Mosul a broken man.
