Who was Immanuel Kant and what was his contribution to law?

[Jurisprudence] Immanuel Kant (1724-1804) was the last forceful philosopher as apostle of natural law theory. He enunciates his theory of knowledge, his famous doctrine of categorical imperative and the ethical postulate of man as an end-in-himself. It is with Kant that the age of natural law theory comes to an end.