What was the main idea in Newton’s Principia?

The Principia states Newton's laws of motion, forming the foundation of classical mechanics; Newton's law of universal gravitation; and a derivation of Kepler's laws of planetary motion (which Kepler first obtained empirically). The Principia is considered one of the most important works in the history of science.

Explanation:

the answer to your question is,

old stone age.

-mabel < 3

answer; archaeologists;