Compare the Crusader success in the campaign of 1115 AD to Saladin's success in 1182 AD.

The initial success of the Christian crusaders came through an exceptional ability to mass troops to repel attacks by a disorganized and a defunct Moslem alliance to defeat a common enemy. Although short on manpower (see above answer), in the earlier period of Christian states in the East, there was a realization of the importance to ward off Islamic attacks in one state to ensure the security of another--and the rulers of these states were …

…Gaza, and had swept through the county of Tripoli (although no major castle or port fell to the Muslims) and advanced into the Principality of Antioch. It was not until the end of the Third Crusade, led by Richard I the Lionheart, that Saladin experienced any real defeats, and although Jerusalem held out against the Christians, the damage to the Muslim resurgence had taken its toll--and was finalized with Saladin's death in the spring of 1193.