"Heretic" is the wrong word. Heresy is moving away from the orthodox doctrine of a religion (a Catholic who converts to Protestantism is a heretic, a Catholic who converts to Islam is an apostate, a Protestant who has never been a Catholic is not a heretic, and a Muslim who has never been a Catholic is not an apostate from the Catholic perspective).

The various Muslim rulers started retaking land. The fall of the County of Edessa was that provoked the Second Crusade and the Kingdom of Jerusalem fell in the Third Crusade. Much of this land was incorporated into the Ayyubid Sultanate of Egypt and Syria (a new kingdom that formed at this time). A good primary source would be ibn Shaddad's biography of the founder of the Ayyubid Sultanate, known in the West as Saladin.