Why did the crusader states finally disappear?

The Crusader states were christian states created by crusaders in Asia Minor, Greece and the Holy land. Only the First Crusade was successful. After freeing Jerusalem most of the crusaders returned to Europe. In 1187 crusaders lost Jerusalem to Saladin. The Fourth crusade was very unsuccessful. It was a decline of the crusader ideal. Muslims recaptured the last Crusader state in 1291 ( fall of the city of Acre ).
Reasons for the fall of the Crusade states:
- the failure of the Third crusade,
- the scandal of the Fourth crusade,
- the decline of the influence of the Catholicism.

The Crusades were spurred on by both religious and political motivations. While the conjunction of the two was enough to make the wars last through many encounters, eventual truces weakened political tensions, leaving insufficient motivations to continue.