The Crusaders take over Jerusalem, and rejoice over their victory. They won due to the lack of unity amongst the Muslim groups. Thus, they have effectively taken over their Holy Lands.
Despite the Muslims losing the city at first due to their lack of unity, they band together. After doing this, they start being able to fight back.
In 1144, they captured Edessa. Edessa was one of the Crusader kingdom's capitols.
The capitol being taken over caused the Christians to launch the second Crusade, picking up the war that Pope Urban II started.
The German army, was defeated badly in Anatolia. Although, the French army (or crusaders) made it to Jerusalem with about 50,000 men.
After making it to Jerusalem, the French Crusaders marched on the city Damascus. Although, Muslims from the city of Edessa came help the city. This lead to the crusaders losing the second Crusade.