The projects main focus is on the early period of modern rational natural law and its impact on law in action and society in northern Europe. Ludvig Holberg was the first author publishing a textbook on natural law in the Danish language (1715). This work was primarily based on the writings of the German philosopher Samuel Pufendorf. Even so, there are differences between the two authors. An analysis of these may demonstrate how ideas of natural law have been spread from the European continent to the peri phery and how the specific legal concepts have been transformed to fit the national requirements in different legal cultures. It can be shown that the scientific-empirical approach to natural law with its truth claim and focus on logical systems had a str ong influence on jurisprudence. Holberg introduced the method of deduction to a juridical audience which did not necessarily have the ability to read Latin texts. This became particularly important after a state examination for legal practitioners was int roduced in 1736. According to Holberg, natural law was not just a philosophical alternative to the existing legal order but had another important function: moralization of human behavior in an absolutistic monarchy. His deep roots in a protestant traditio n and his lack of juridical expertise were the main reasons why he did not follow his contemporary Thomasius or Hojer who argued for a stricter separation of law and morals. Where to draw the line between law and morals has been discussed ever since and h as become of new practical relevance in the light of recent tendencies of legal harmonization and especially human rights protection. This discourse is still based on the arguments which were developed in the 17th and 18th century. To reveal the underlyin g values and the prevailing ideal of justice in this period of time may contribute to a better understanding of the evolution of national legal systems and European legal culture.