Grotius was a major figure in the fields of philosophy, political theory and law during the 16th and 17th centuries.
Along with the earlier works of Francisco de Vitoria and Alberico Gentili, his writings laid the foundations for international law, based on natural law in its Protestant side. Two of his books have had a lasting impact in the field of international law: De jure belli ac pacis (On the Law of War and Peace) dedicated to Louis XIII of France and the Mare Liberum (The Free Seas) for which Grotius has been called the "father of international law.
Grotius has also contributed significantly to the evolution of the notion of rights. Before him, rights were, above all, perceived as attached to objects; after him, they are seen as belonging to persons, as the expression of an ability to act, or as a means of realizing something.
