Early Renaissance thinkers followed Plato in emphasizing mathematics as the key to understanding nature. He had established the philosophy that the physical world was merely an imperfect reflection of the perfect forms. However, during the Renaissance the concept that the physical world was indeed a perfect reflection of Divine intent. These Neo Platonists included Copernicus, Galileo, and Kepler, all of whom used geometric measurement to begin to explain the structure and motion of the physical world. Although the culmination of their efforts came very late in the Renaissance, their efforts led to the foundation that Isaac Newton established in the 1700's through his calculus to perfectly describe motion and rates of change.