The Legacy of Hugo Grotius
A child prodigy, Hugo Grotius studied at Leiden University at age eleven. He became world-famous as a legal scholar, wrote books and poems, and served as pensionary of Rotterdam. He also advised Johan van Oldenbarnevelt, who clashed with Prince Maurice. Maurice won: Johan was executed, and Hugo was locked up in this room.

After escaping Loevestein, Hugo lived in exile in France. There, in 1621, he published his most important book: On the Law of War and Peace – a milestone in the rules of war.

Rules of War
In this work, Grotius set out rules for war based on natural rights that apply to everyone, everywhere – beyond culture, faith, or power. This was groundbreaking. He distinguished between when war may begin and how it must be fought: only to restore justice, with limited violence, and with protection for civilians, prisoners, and cultural heritage.

 

Portrait of Hugo Grotius. Studio Van Mierevelt, 1631. Collection Rijksmuseum Slot Loevestein.

Rules Before and During War
On the Law of War and Peace has three parts:

  1. Book I: When war may be justified.
  2. Book II (Jus ad Bellum): Three just causes for war – self-defense, recovery of property, and punishing wrongdoing.
  3. Book III (Jus in Bello): Rules for conduct during war. This still forms the basis of modern humanitarian law.

Mare Liberum
Grotius laid the the foundations of international maritime law with his book Mare Liberum (or The Freedom of the Seas), published in 1604. Commissioned by the Dutch East India Company, it argued that the seas belong to everyone. This idea justified Dutch trade, as well as future colonial conquest.

Books on display:

  • De Iure Belli ac Pacis (On the Law of War and Peace). Latin edition, 1625, printed 1680. Collection Rijksmuseum Slot Loevestein.
  • Treating of the Rights of War & Peace. English edition, 1625, printed 1682. Collection Rijksmuseum Slot Loevestein.
  • Mare Liberum (The Free Sea). Hugo Grotius, 1609. Edition 1618. Collection Rijksmuseum Slot Loevestein.
  • The “real” chest? For years, this was thought to be the chest Hugo used to escape. In 1981 it was revealed to be fake. Yet, together with two others in Dutch museums, it remains a symbol of his story – and is part of the Dutch national canon.
  • The Loevestein Chest. Origin unknown, ca. 1800. Collection Friends of Loevestein Castle.

Click here for the Dutch exhibition page