Development of International

Foundations in Antiquity and the Middle Ages

• Early Treaties: Concepts like treaties and diplomatic relations trace back to ancient times. Early examples include agreements between Mesopotamian city-states (c. 2100 BCE) and the treaty between Egypt's Ramses II and the Hittite king (c. 1258 BCE) establishing "eternal peace."

• Ancient Greece: City-states developed rules for inter-state conduct, particularly regarding war and peace, though these primarily applied among Greek states.

• Roman Law (Jus Gentium): The Roman Empire developed the concept of Jus Gentium (Law of Nations) to govern interactions between Roman citizens and foreigners. This system, rooted in the Greek idea of Natural Law, focused on universal principles of fairness and influenced later international legal thought.

• Early Islamic Law: Developed principles concerning military conduct, the treatment of prisoners of war, and guidelines for ceasing hostilities, considered precursors to International Humanitarian Law.

• Medieval Europe: The period saw the development of various supranational rules like Canon Law (Church law), the Law Merchant (governing trade), and maritime codes like the Rolls of Oléron, which regulated transnational interactions.

The Rise of Modern International Law (16th–18th Centuries)

• The Renaissance & State Consolidation: The rise of European nation-states, increasing trade, and ocean navigation necessitated a more formal, secular set of rules to govern their relations.

• The Spanish School of Thought: Figures like Francisco de Vitoria (16th century) explored the rights of indigenous peoples and emphasized that international law was founded on Natural Law.

• Hugo Grotius (1583–1645): Often called the "Father of International Law."

• o His 1625 work, De Jure Belli ac Pacis (On the Law of War and Peace), systematized international law and, crucially, began the process of separating it from theological principles, grounding it in reason and natural law principles recognizable by states.

• Peace of Westphalia (1648): This treaty, ending the Thirty Years' War, is a watershed moment.

• o It established the modern concept of the Sovereign Nation-State, granting each sovereign independent authority within its territory, which is the foundational principle of the current international legal system.

• Naturalist vs. Positivist Schools: Following Grotius, two main schools developed:

• o Naturalists: Argued international law derived from universal moral and rational principles (Natural Law).
• o Positivists: Argued international law was based on the actual practice and consent of states (treaties and customs). Positivism eventually became dominant.

The 19th Century: Concert and Codification

• Congress of Vienna (1815): Established a post-Napoleonic European order (Concert of Europe), introducing a framework for collective security and diplomatic regulation, including the regulation of diplomatic agents.

• Increased Multilateralism: International law broadened beyond war and peace to include commerce, communication, and social issues.

• Codification Efforts: States began formalizing rules through multilateral treaties:

• o Geneva Convention (1864): The first major treaty on the treatment of the wounded in armed forces, laying the foundation for International Humanitarian Law (IHL).
• o Hague Peace Conferences (1899 and 1907): Focused on the laws of war and peaceful dispute settlement. They led to the establishment of the Permanent Court of Arbitration (PCA).

• The Term: Jeremy Bentham coined the term "International Law" in 1789, replacing the older term "Law of Nations."

The 20th Century and Contemporary Era

• Post-World War I:

• o Treaty of Versailles (1919): Established the League of Nations, the first intergovernmental organization aimed at preventing war.
• o Permanent Court of International Justice (PCIJ): Created as part of the League system.

• Post-World War II:

• o United Nations (UN) (1945): Founded as the successor to the League, prohibiting the armed force against the territorial integrity or political independence of any state (Article 2(4) of the UN Charter) and driving the development of multilateral treaties.
• o International Court of Justice (ICJ): The principal judicial organ of the UN.
• o Decolonization: Led to a truly global international law as new states infused it with diverse interests and cultural backgrounds, moving it beyond its Eurocentric origins.
• o Human Rights: The Universal Declaration of Human Rights (UDHR) (1948) and subsequent treaties codified individual human rights, making the individual a key concern of international law.

• Late 20th Century & Beyond:

• o Law of the Sea (UNCLOS, 1982): Comprehensive framework governing all maritime zones.
• o International Criminal Court (ICC) (2002): Established to prosecute individuals for war crimes, crimes against humanity, and genocide.
• o Environmental Law: Proliferation of treaties addressing global issues like climate change (e.g., Paris Agreement) and biodiversity.