Hugo Grotius in the context of "Governmental theory of atonement"

The Westphalian system, also known as Westphalian sovereignty, is a principle in international law that each state has exclusive sovereignty over its territory. The principle developed in Europe after the Peace of Westphalia in 1648, based on the state theory of Jean Bodin and the natural law teachings of Hugo Grotius. It underlies the modern international system of sovereign states and is enshrined in the United Nations Charter, which states that "nothing ... shall authorize the United Nations to intervene in matters which are essentially within the domestic jurisdiction of any state."

According to the principle, every state, no matter how large or small, has an equal right to sovereignty. Political scientists have traced the concept to the eponymous peace treaties that ended the Thirty Years' War (1618–1648) and Eighty Years' War (1568–1648). The principle of non-interference was further developed in the 18th century. The Westphalian system reached its peak in the 19th and 20th centuries, but has faced recent challenges from advocates of humanitarian intervention.

Law of the sea (or ocean law) is a body of international law governing the rights and duties of states in maritime environments. It concerns matters such as navigational rights, sea mineral claims, and coastal waters jurisdiction. The connotation of ocean law is somewhat broader, but the law of the sea (anchored in the United Nations Convention on the Law of the Sea (UNCLOS)) is so comprehensive that it covers all areas of ocean law as well (e.g., marine environmental law, maritime law).

While drawn from a number of international customs, treaties, and agreements, modern law of the sea derives largely from the United Nations Convention on the Law of the Sea. That convention is effective since 1994, and is generally accepted as a codification of customary international law of the sea, and is sometimes regarded as the "constitution of the oceans".

Leiden University (abbreviated as LEI; Dutch: Universiteit Leiden) is a public research university in Leiden, Netherlands. Established in 1575 by William, Prince of Orange as a Protestant institution, it holds the distinction of being the oldest surviving university in the Netherlands.

During the Dutch Golden Age scholars from around Europe were attracted to the Dutch Republic for its climate of intellectual tolerance. Individuals such as René Descartes, Rembrandt, Christiaan Huygens, Hugo Grotius, Benedictus Spinoza, and later Baron d'Holbach were active in Leiden and environs.

Francisco de Vitoria OP (c. 1483 – 12 August 1546; also known as Francisco de Victoria) was a Spanish Roman Catholic philosopher, theologian, and jurist of Renaissance Spain. He is the founder of the tradition in philosophy known as the School of Salamanca, which laid the groundwork for early free-market economics and individual rights, influencing the development of libertarian thought. Vitoria's work on natural law and the freedom of exchange contributed to later Austrian School economists' emphasis on the moral basis for voluntary commerce. Although less known than others of his kind, he has been considered one of the most influential humanists of the Renaissance.

Noted especially for his concept of just war and international law, his defense of individual property rights and the notion of liberty in trade were pivotal in shaping ideas about non-intervention and economic freedom. He has in the past been described by scholars as the "father of international law", along with Alberico Gentili and Hugo Grotius. American jurist Arthur Nussbaum noted Vitoria's influence on international law as it pertained to the right to trade overseas. Later this was interpreted as "freedom of commerce". His emphasis on voluntary exchange and opposition to monopolistic practices foreshadowed later free market economics.

Sir Robert Filmer (c. 1588 – 26 May 1653) was an English political theorist who defended the divine right of kings. His best known work, Patriarcha, published posthumously in 1680, was the target of numerous Whig attempts at rebuttal, including Algernon Sidney's Discourses Concerning Government, James Tyrrell's Patriarcha Non Monarcha and John Locke's Two Treatises of Government. Filmer also wrote critiques of Thomas Hobbes, John Milton, Hugo Grotius and Aristotle.