More people start exploring...why?
Economy: The products from the east make a lot of money
Religion: The Europeans desperately wanted to spread the word of God all over the world (holy mission).
Politics: European monarchs get a chance to expand their power. This is called expansion (more land = more influence).
Tools: In the fifteenth century a lot of new inventions become available to make travel by sea easier.
Knowledge: New maps of the world become available (antiquity).