Ascalon was Fatimid Egypt's greatest and most important frontier fortress. The Battle of Ascalon was fought outside the city in 1099 in the aftermath of the First Crusade and the fall of Jerusalem to the Crusaders. Although the crusaders were victorious, internal disputes in their camp allowed Ascalon to remain in Egyptian hands. Thereafter, the Fatimids were able to launch raids into the kingdom every year from this fortress, and the southern border of the crusader kingdom remained unstable. If this fortress fell, then the gateway to Egypt would be open. Therefore, the Fatimid garrison in Ascalon remained strong and large.