What is a major focus of renaissance art as opposed to medieval art?

What is a major focus of renaissance art as opposed to medieval art?
Most medieval art was commisioned by the Church (who had the money for such things) and therefore depictions were things like Jesus or other people from the Bible, or any desired religious theme. Artists had a quite low position in society and were dependant upon such commissions. Pictures and sculptures were stylized and idealized as best the artist could to reflect the holy nature of the subject matter.
During the Renaissance, artists were also commissioned by the church, but also increasingly by wealthy citizens, many of whom wanted non-religious art like portraits of themselves or loved ones, or illustrations of a favorite secular story. There was a great interest in science and nature at the time and a retreating of the idea that the physical, secular world was automatically sinful and evil. As a result of this change in thinking, artists like Leonardo and Michelangelo (to name the most well-known) studied natural processes and forms; including the human body, and much more lifelike depictions were created now that a new respect was felt for these forms.