How did the crusades affect the political development of europe?

The first Crusade was successful for European leaders they were able to have the some cities such as Jerusalem, Acre, Bethlehem, and Antioch. But after that the things goes wrong.

The political perspective was a failure.

Although they did not fully achieve their religious goal, the Crusades promoted major changes across Europe, such as the reopening of the Mediterranean to European shipping and trade. This made it possible to intensify trade between the West and the East, largely interrupted by Muslim expansion.

its many islands, high mountains, and remote peninsulas isolated population centers.

the roman empire began to fall