How did the crusades bring about the end of the dark ages in europe? what was the "spark in the dark" that ended the "darkness" of the middle ages?

One of the ways in which the Crusades brought about the end of the Dark Ages in Europe was that they (by accident) opened up a variety of new trade routes, which led to increased travel and cultural diffusion. This was thought to be the "spark in the dark" as the Enlightenment. 

The muslims ruler the mandated and cultural toleration was osman

Farm land would be my guess