The Crusades were very important to develop trade in Europe. The Crusaders went from Europe to the Middle East and came in contact with other cultures and people. With that, Europeans were able to learn things from the Arabs such as mathematics and the numeral system. Also, they tasted new food and goods which they brought back to Europe and people started to taste and demand.
This eventually made possible for trade to be consistent between both regions which also helped to develop a currency system that enabled trade.
Marco Polo was the first European to reach China and he wrote a book that made possible for others to want to visit the lands and start trading with Asian countries that had several goods and products to trade with Europe. Marco Polo was also very important for cartography that helped the European voyages of exploration later, he never drew a map himself but his notes made the drawing possible later, which eventually helped European Countries to trade with Asia and even with the Americas.
