Newton's Law of Universal Gravitation/Historical Note

Historical Note on Newton's Law of Universal Gravitation
The popular tale has it that had the idea while lying in the garden at his home in Woolsthorpe between the years of $1665$ and $1667$ and watching an apple fall from a tree.

However, the inverse square law was in fact conjectured by in $1684$, but he was unable to do anything to prove his conjecture. He discussed this with and, who claimed he had a proof of it. However, disbelieved him.

Some months later, had the chance to ask  how the planets would move under such a law of gravitation. The latter answered immediately that it would be an ellipse, and that he had already calculated it.

The mathematical work that he had performed to prove had supposedly been deduced from Kepler's Laws of Planetary Motion.

Having been thus spurred on by, went ahead to write and publish his.