How did the Crusades directly cause the Renaissance?

They opened the door for the travelers to visit East, but also spread the learning on Ancient Greek civilization to the west.

Explanation:

Although Crusades were mostly connected with the religious wars from the 11th until 13th Century, they established certain connections between East and West and caused the revival of interest for the knowledge of ancient period. Many scholars were re-discovered, and that is why Crusades had a good effect when looking through that perspective.

he impacted the society ith his knowwdge and advance our research by years to come