in 1140 jamal ad-din died, and mu'in ad-din continued to rule as regent for jamal ad-din's son mujir ad-din. that year, mu'in ad-din besieged banias with help from king fulk of jerusalem and prince raymond of antioch; mu'in ad-din offered 20 000 pieces of gold per month to pay for their expenses. when it was captured, mu'in ad-din handed it over to fulk and returned to damascus. a more thorough alliance, to protect damascus against zengi, was negotiated during a visit by mu'in ad-din to jerusalem, accompanied by the future chronicler usamah ibn munqidh.