who came up with the three laws of gravity
In the same way he found that the amount of the gravity between the Sun and a planet is Force = Ks  (Sun mass) / (r)2. Using his third law of motion, Newton reasoned that these forces must be of the same magnitude but acting in the opposite directions. This led him for form his Universal Law of Gravitation.
It took place 111 years after the publication of Newton's Principia and approximately 71 years after his death. Newton's law of gravitation resembles Coulomb's law of electrical forces, which is used to calculate the magnitude of the electrical force arising between two charged bodies.