In the Battle of Yibneh (Yibna) in 1123, a Crusader force led by Eustace Grenier crushed a Fatimid army from Egypt sent by vizier Al-Ma'mun between Ascalon and Jaffa.
Meanwhile, Jerusalem was weakened by the capture of King Baldwin II by the Artuqids in northern Syria; the kingdom was at this time governed by the regent Eustace Grenier.
In this era, the Egyptian armies usually deployed with Sudanese archers on foot, supported by dense formations of Arab and Berber light cavalry.
At Yibna, near the later site of the castle of Ibelin (built 1141), the Fatimid invasion force encountered the crusader army of knights and men-at-arms on horseback and spearmen and bowmen on foot.
[2] As Fulcher of Chartres says, this battle did not last long because when our foes saw our armed men (meaning the mounted knights and men-at-arms) advance in excellent order against them their horsemen immediately took flight as if completely bewitched, going into a panic instead of using good sense.