The article provides a theological analysis of the figure of Hugo Grotius, one of the founders of the modern international law, who had a great influence for the peace-process in the last time of the Thirty Years’ War. He also played a role in the European history of the Enlightenment and secularisation eras. In our time analysis of Grotius’s heritage is connected with new liberal understanding of religion in the spirit of tolerance, as well as with the connection between religion and politics. Grotius recommends to build a foundation of law and peace without any use or misuse of the name of God — could it be helpful also in our time? The German theologian Dietrich Bonhoeffer expected a non-religious time, but we have to see a growing influence of religion for political decisions and in consequence a growing mistrust against religion in the secular society. But it gives also an overview about new literature to Grotius and about his life and works and his significance in contemporary theological discussions. A short point is the reception of Grotius in the Russian tradition. The article is based on the report made at the historical conference devoted to the Thirty Years War (Saint-Petersburg, Russia, 2018).