The bubonic plague, or "Black Death" originated in China in the late 1340's. Spread by fleas and rats, it devastated Central Asia and Europe. Many populations were decreased by 1/3 of their original inhabitants.
Production of artistic materials came to a halt as a result. So emerged an anti materialistic and pessimistic outlook in the artistic community. At the same time, art was also looked to to provide religious support. According to our book, the plague encouraged commissions of devotional images. Religious beliefs grew as people began to seclude themselves in order to avoid the plague. Artists also began to make documentations of the plague.
Humanism was gained as result of the plague. Softening of lines and lighting, natural expressions, and more realistic representations of faces are parts of humanism. In my opinion, this realism was a result of a focus on life. As people were dying, artists became focused on the real images of humanity, instead of medieval symbols. The presence of death around them may have spurred artists to create more rapidly, for every creation could have been their last. This potential time limit, combined with the will to encourage, inspire, or get paid by people to create these inspirations, may have fueled these humanistic accomplishments.
Architecture was also impacted, as the massive amounts of sickness encouraged hospital construction, according to the book.
As the Renaissance continued and the plague began to subdue, a new middle class developed. They had more money and leisure time, and more time to enjoy art.