Before WW1, that was the Ottoman empire. The arab provinces of the empire were unhappy, and contacted the entente. The agreed to revolt against the turks in exchange for control over all that area. The arabs fought against the turks, with the help of the entente, however as soon as the war ended, the entente revealed their actual plan: the sykes-picot agreement. Basically they got backstabbed.

In this agreement they would divide the area, give it new names, put it under foreign control. Since then the area is a constant mess. By design.

Then every other year they finance some rebel group or army here and there so there's never peace.