At the end of 1138, the situation of the Kingdom of Jerusalem was not very strong. King Foulques was obliged to adopt a defensive attitude after the fall of the stronghold of Ba'rin, in the South of the kingdom. Transjordania was infested by bands of plunderers who constantly executed raids throughout the kingdom.
During the summer of 1139, Thierry d'Alsace, Count of Flandre and (by marriage) a member the family of King Foulques, arrived in Jerusalem as his pilgrimage. He was accompanied by a small army. Foulques took advantage of his pilgrimage to set up an expedition to dislodge and destroy the plunderers settled in the mountains in the region of Galaad.
The armies of Foulques and Thierry besieged the fortress of the plunderers located between mount Jil'ad and 'Ajlûn. During this long siege, Turkomans, seeing the kingdom of Jerusalem without protection raided and plundered the village of Tecua (Teqoa).
The only military force defending Jerusalem was the Templars. They raised all the available armed people to confront the Turkomans. When the Frankish armies of Foulques and Thierry approached, the plunderers disbanded in the plains of Ascalon and refused to fight.
The Franks construed this as a win and set about pursuing their enemy. This mistake separated the French force. Noticing this, the Turkomans regrouped and attacked the Franks. The Turkomans cut them to pieces.
Seeing this, Robert de Craon rallied the Knights Templar to head towards the front of the fight, in order to protect the flight of the Frankish knights.
A great many Frankish Knights were killed and more than half of the Templars died.
What is generally considered as a little skirmish was in reality the 'dress rehearsal' for what happened less than 50 years later at Hattin...