Hugo Grotius - international_law @ ウィキ

Hugo Grotius (also known as Huig de Groot or Hugo de Groot; 10 April 1583 – 28 August 1645) worked as a jurist in the Dutch Republic. With Francisco de Vitoria and Alberico Gentili he laid the foundations for international law, based on natural law. He was also a philosopher, theologian, Christian apologist, playwright, and poet.(Wikipedia)

Publications: On the Law of War and Peace(1625).

He argued that "To proceed the war and during the war, there must be common law that must be followed by the nations"

Source from Wikipedia
Hugo Grotius Wikipedia