Page "Mechanics" Paragraph 24

There is some dispute over priority of various ideas: Newton's Principia is certainly the seminal work and has been tremendously influential, and the systematic mathematics therein did not and could not have been stated earlier because calculus had not been developed.

However, many of the ideas, particularly as pertain to inertia ( impetus ) and falling bodies had been developed and stated by earlier researchers, both the then-recent Galileo and the less-known medieval predecessors.

Precise credit is at times difficult or contentious because scientific language and standards of proof changed, so whether medieval statements are equivalent to modern statements or sufficient proof, or instead similar to modern statements and hypotheses is often debatable.