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.

This tale has the feel of an off-the-cuff comment that may have made during the course of an interview with a journalist of the time, or whatever the equivalent may have been.

The children's version of the tale has it that the apple hit him on the head.

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  what law of attraction would cause the planets to move in an elliptical orbit. answered immediately that it would be an inverse square law, and claimed to have already calculated it.

Some sources state that the question was posed the other way round: that asked how the planets would behave under a central force obeying the inverse square law.

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.