The stage has now been set for the closer delineation of the natural law, the result of the efforts of the great scholastic theologians working on the rich material they found in the tradition. The elements in that tradition, as has been seen, were basically three: (1) a conception of the natural law, originally Stoic with a background in the pre-Socratics, Plato and Aristotle, translated into the Roman world, popularized by Cicero and finding its authoritative expression in the Roman law; (2) a conception of the natural law, complementing the preceding one, but tributary to St. Paul and the elaboration of his thought by the Fathers and ecclesiastical writers; and (3) the radical re-shaping of the Christian natural law in its identification, by Gratian and his followers, with what is found in the law and the gospel. The future history of the concept of natural law will be determined by the weaving together of these strands in the special environment of scholastic philosophy and theology. It is part of the thesis of this book that the profile that resulted in the work of St. Thomas Aquinas gets as close as is humanly possible to the natural law and that it has hardly been improved upon by his successors. To see this achievment in its context, we must first look-of necessity briefly and selectively — at some of his immediate forerunners.