The Islamic charity Mujama al-Islamiya was established in Gaza by Sheikh Ahmed Yassin in 1973, and started to offer clinics, blood banks, day care, medical treatment, meals and youth clubs. The centre plays an important role for providing social care to the people, particularly those living in refugee camps. It also extended financial aid and scholarships to young people who wanted to study in Saudi Arabia and the West.
In 1984, the Israeli military raided a mosque and found a cache of weapons. Sheikh Yassin was jailed. He was released after a year and continued to expand Mujama's reach across Gaza.