After the horrific plague that stormed through Europe people wanted to celebrate life. The growth of trade exposed more people to new goods and ideas and new attitudes spread across Europe that helped to create new ways of thinking. People in Medieval times believed that you were here to suffer and avoid life's pleasures in order to please God.
Humanists believed that God wanted us to enjoy life. Humanism stressed the importance of the individual power. The goal was to create well rounded individuals and encourage people to strive for greater things while still being good Christians.
The printing press helped to spread new ideas, discoveries, and knowledge. People were able to share their ideas by publishing them in books which made them cheaper. More people were getting literate which marked the end of a dark middle ages.