This law of the third century has little resemblance to the old Roman law, so severe on the weak. The jurisconsults adopt the ideas of the Greek philosophers, especially of the Stoics. They consider that all men have the right of liberty: "By the law of nature all men are born free," which is to say that slavery is contrary to nature. They also admit that a slave could claim redress even against his master, and that the master, if he killed his slave, should be punished as a murderer. Likewise they protect the child against the tyranny of the father.
It is this new law that was in later times called Written Reason. In fact, it is a philosophical law such as reason can conceive for all men. And so there remains no longer an atom of the strict and gross law of the Twelve Tables. The Roman law which has for a long time governed all Europe, and which today is preserved in part in the laws of several European states is not the law of the old Romans. It is constructed, on the contrary, of the customs of all the peoples of antiquity and the maxims of Greek philosophers fused together and codified in the course of centuries by Roman magistrates and jurisconsults.