Either the second law of motion, the second law of theromodynamics,the universal law of gravitation, or the law of inertia
Principia Mathematica explained the law of gravity and laws of motion in mathematical terms.
Newton's three laws of motion.
Philosophiae Naturalis Principia Mathematica
Philosophiæ Naturalis Principia Mathematica, Latin for "Mathematical Principles of Natural Philosophy", often called the Principia ("Principles"), is a work in three books by Sir Isaac Newton, first published July 5 1687.
Isaac Newton published his Principia Mathematica in 1687 which included his laws of motion.
The Principia was created in 1898.
Principia Mathematica was created in 1913.
Principia Sardonica was created in 2004.
Principia Discordia was created in 1965.
Principia Ethica was created in 1903.
Principia Cybernetica was created in 1989.
Principia College was created in 1910.