Whose law is it anyway?

Newton's first law of motion - which says a body at rest will remain at rest, and a body in motion will remain in motion at a constant velocity in a straight line unless acted upon by a force - was published in 1687.  So?  Well, although it is known throughout the world as Newton's First Law, the self-same rule had been published some forty years earlier in a book by René Decartes (he of the "I think, therefore I am" fame - see post dated 6/9/10).