Hugo Grotius (1583–1645)

The Dutch scholar of law Hugo Grotius is considered the founder of classical international law, which he developed in his works (in particular De jure belli ac pacis, 1625) from principles of natural law as a part of the positive and reason-bound legal order encompassing all states and all people. Grotius thus placed international law on the basis of equality between states and mutuality. Grotius's theories were first applied in practice in the Peace of Westphalia (1648).

Willem Jabszoon Delff (1580–1638), portrait of Hugo Grotius (1583–1645), copper engraving after a painting by Michiel van Mierevelt (1567–1641), 1632; source: Grotius, Hugo: Annotationes in Libros Evangeliorum..., Amsterdam 1641 [title engraving], public domain.