What caused Europe's population to increase, to provoke its interest in trade, and provided its population with large amounts of gold and silver?

The Columbian Exchange.

Explanation:

The Columbian Exchange is the transfer of technology, animals, humans, diseases between America, West Africa and the Old World. This has a close relation with European colonisation in the New World. This events empowered Europe with goods, gold and silver. The colonies meant a lot for the Old World, because they were lacking of some goods that they could found in America.

the treaty of versailles