Kepler's laws of planetary motion explaining how the planets' speeds varied, and using elliptical orbits rather than circular orbits with epicycles. Isaac Newton showed in 1687 that relationships like Kepler's would apply in the Solar System to a good approximation, as a consequence of his own laws of motion and law of universal gravitation. Kepler's laws improved the model of Copernicus. If the eccentricities of the planetary orbits are taken as zero, then Kepler basically agreed with Copernicus: The eccentricities of the orbits of those planets known to Copernicus and Kepler are small, so the foregoing rules give fair approximations of planetary motion, but Kepler's
Valerio-Horatian Laws on the plebiscites, there were three instances of such law. There were two other laws on appeal which were proposed by two consuls who were also members of the Valeria family, one by Publius Valerius Publicola in 509 BC and one by Marcus Valerius Corvus in 300 BC. Two other laws which provided for the plebiscites to be binding on the whole people were also proposed, one by Quintus Publilius Philo in 339 BC and one by Quintus Hortensius in 287 BC. This has led some historians to argue that in both cases the first and second laws are unhistorical