1. He had conducted most of his research in the early 16th century. is was widely considered to be the beginning of the modern era, because of the extreme change in ideology, technology, and the global perspective. And countless calculations and observations, made conclusions which did not only changed the way mankind looked at the heavens, but also laid the foundations for other theories from other astronomers such as Galileo Galilei and Giordano Bruno.
I hope this helps, and I am sorry I couldn't find the second one.