Hugo Grotius

Grotius at age 16, by Jan Antonisz. van Ravesteyn, 1599

Born in Delft during the Dutch Revolt, Hugo Grotius was the first child of Jan Cornets de Groot and Alida van Overschie. His father was a man of learning, once having studied with the eminent Justus Lipsius at Leiden University,[7] as well as of political distinction. His family was considered Delft patrician as his ancestors played an important role in local government since the 13th century.[8]

Jan de Groot was also translator of Archimedes and friend of Ludolph van Ceulen. He groomed his son from an early age in a traditional humanist and Aristotelian education.[9] A prodigious learner, Hugo entered the Leiden University when he was just eleven years old.[8] There he studied with some of the most acclaimed intellectuals in northern Europe, including Franciscus Junius, Joseph Justus Scaliger, and Rudolph Snellius.[10]

At age 16 (1599) he published his first book: a scholarly edition of the late antique author Martianus Capella's work on the seven liberal arts, Martiani Minei Felicis Capellæ Carthaginiensis viri proconsularis Satyricon. It remained a reference for several centuries.[11]

In 1598, at the age of 15 years, he accompanied Johan van Oldenbarnevelt to a diplomatic mission in Paris. On this occasion, the King Henri IV of France would have presented Grotius to his court as "the miracle of Holland".[12] During his stay in France, he passed or bought a law degree from the University of Orleans.[13]

In Holland, Grotius earned an appointment as advocate to The Hague in 1599[14] and then as official historiographer for the States of Holland in 1601. It was on this date that the Dutch tasked him to write their story to better stand out from Spain; Grotius is indeed contemporary with the Eighty Years' War between Spain and the Netherlands.[13] His first occasion to write systematically on issues of international justice came in 1604, when he became involved in the legal proceedings following the seizure by Dutch merchants of a Portuguese carrack and its cargo in the Singapore Strait.

In 1608 he married Maria van Reigersberch; they had three daughters and four sons.[13]

Page written in Grotius' hand from the manuscript of De Indis (circa 1604/05)

The Dutch were at war with Spain; although Portugal was closely allied with Spain, it was not yet at war with the Dutch. Near the start of the war, Grotius's cousin captain Jacob van Heemskerk captured a loaded Portuguese carrack merchant ship, Santa Catarina, off present-day Singapore in 1603.[15] Heemskerk was employed with the United Amsterdam Company (part of the Dutch East India Company), and though he did not have authorization from the company or the government to initiate the use of force, many shareholders were eager to accept the riches that he brought back to them.[16]

Not only was the legality of keeping the prize questionable under Dutch statute, but a faction of shareholders (mostly Mennonite) in the Company also objected to the forceful seizure on moral grounds, and of course, the Portuguese demanded the return of their cargo. The scandal led to a public judicial hearing and a wider campaign to sway public (and international) opinion. It was in this wider context that representatives of the Company called upon Grotius to draft a polemical defence of the seizure.[16]

Portrait of Grotius at age 25 (Michiel Jansz. van Mierevelt, 1608)

The result of Grotius' efforts in 1604/05 was a long, theory-laden treatise that he provisionally entitled De Indis (On the Indies). Grotius sought to ground his defense of the seizure in terms of the natural principles of justice. In this, he had cast a net much wider than the case at hand; his interest was in the source and ground of war's lawfulness in general. The treatise was never published in full during Grotius' lifetime, perhaps because the court ruling in favor of the Company preempted the need to garner public support.

In The Free Sea (Mare Liberum, published 1609) Grotius formulated the new principle that the sea was international territory and all nations were free to use it for seafaring trade. Grotius, by claiming 'free seas' (Freedom of the seas), provided suitable ideological justification for the Dutch breaking up of various trade monopolies through its formidable naval power (and then establishing its own monopoly). England, competing fiercely with the Dutch for domination of world trade, opposed this idea and claimed in John Selden's Mare clausum (The Closed Sea), "That the Dominion of the British Sea, or That Which Incompasseth the Isle of Great Britain, is, and Ever Hath Been, a Part or Appendant of the Empire of that Island."[17]

It is generally assumed that Grotius first propounded the principle of freedom of the seas, although all countries in the Indian Ocean and other Asian seas accepted the right of unobstructed navigation long before Grotius wrote his De Jure Praedae (On the Law of Spoils) in the year of 1604. Additionally, 16th century Spanish theologian Francisco de Vitoria had postulated the idea of freedom of the seas in a more rudimentary fashion under the principles of jus gentium.[18] Grotius's notion of the freedom of the seas would persist until the mid-20th century, and it continues to be applied even to this day for much of the high seas, though the application of the concept and the scope of its reach is changing.

Aided by his continued association with Van Oldenbarnevelt, Grotius made considerable advances in his political career, being retained as Oldenbarnevelt's resident advisor in 1605, Advocate General of the Fisc of Holland, Zeeland and Friesland in 1607, and then as Pensionary of Rotterdam (the equivalent of a mayoral office) in 1613.[19] Also in 1613, following the capture of two Dutch ships by the British, he was sent on a mission to London,[20] a mission tailored to a man who wrote Mare liberum [The Free Seas] in 1609. However, it was opposed by the English by reason of force and he didn't obtain the return of the boats.[20]

In these years a great theological controversy broke out between the chair of theology at Leiden Jacobus Arminius and his followers (who are called Arminians or Remonstrants) and the strongly Calvinist theologian, Franciscus Gomarus, whose supporters are termed Gomarists or Counter-Remonstrants.

Leiden University "was under the authority of the States of Holland – they were responsible, among other things, for the policy concerning appointments at this institution, which was governed in their name by a board of Curators – and, in the final instance, the States were responsible for dealing with any cases of heterodoxy among the professors."[21] The domestic dissension resulting over Arminius' professorship was overshadowed by the continuing war with Spain, and the professor died in 1609 on the eve of the Twelve Years' Truce. The new peace would move the people's focus to the controversy and Arminius' followers. Grotius played a decisive part in this politico-religious conflict between the Remonstrants, supporters of religious tolerance, and the orthodox Calvinists or Counter-Remonstrants.[20]

Edict of toleration

Led by Oldenbarnevelt, the States of Holland took an official position of religious toleration towards Remonstrants and Counter-Remonstrants. Grotius, (who acted during the controversy first as Attorney General of Holland, and later as a member of the Committee of Counsellors) was eventually asked to draft an edict to express the policy of toleration.[24] This edict, Decretum pro pace ecclesiarum was completed in late 1613 or early 1614. The edict put into practice a view that Grotius had been developing in his writings on church and state (see Erastianism): that only the basic tenets necessary for undergirding civil order (e.g., the existence of God and His providence) ought to be enforced while differences on obscure theological doctrines should be left to private conscience.[25]

Statue of Hugo Grotius in Delft, the Netherlands

The edict "imposing moderation and toleration on the ministry", was backed up by Grotius with "thirty-one pages of quotations, mainly dealing with the Five Remonstrant Articles."[23] In response to Grotius' Ordinum Pietas, Professor Lubbertus published Responsio Ad Pietatem Hugonis Grotii in 1614. Later that year Grotius anonymously published Bona Fides Sibrandi Lubberti in response to Lubbertus.[23]

Jacobus Trigland joined Lubberdus in expressing the view that tolerance in matters of doctrine was inadmissible, and in his 1615 works Den Recht-gematigden Christen: Ofte vande waere Moderatie and Advys Over een Concept van moderatie[26] Trigland denounced Grotius' stance.

In late 1615, when Middelburg professor Antonius Walaeus published Het Ampt der Kerckendienaren (a response to Johannes Wtenbogaert's 1610 Tractaet van 't Ampt ende authoriteit eener hoogher Christelijcke overheid in kerckelijkcke zaken) he sent Grotius a copy out of friendship. This was a work "on the relationship between ecclesiastical and secular government" from the moderate counter-remonstrant viewpoint.[23] In early 1616 Grotius also received the 36 page letter championing a remonstrant view Dissertatio epistolica de Iure magistratus in rebus ecclesiasticis from his friend Gerardus Vossius.[23]

The letter was "a general introduction on (in)tolerance, mainly on the subject of predestination and the sacrament...[and] an extensive, detailed and generally unfavourable review of Walaeus' Ampt, stuffed with references to ancient and modern authorities."[23] When Grotius wrote asking for some notes "he received a treasure-house of ecclesiastical history. ...offering ammunition to Grotius, who gratefully accepted it".[23] Around this time (April 1616) Grotius went to Amsterdam as part of his official duties, trying to persuade the civil authorities there to join Holland's majority view about church politics.

In early 1617 Grotius debated the question of giving counter-remonstrants the chance to preach in the Kloosterkerk in The Hague which had been closed. During this time lawsuits were brought against the States of Holland by counter-remonstrant ministers and riots over the controversy broke out in Amsterdam.

Arrest and exile

Loevestein Castle at the time of Grotius' imprisonment in 1618–21

As the conflict between civil and religious authorities escalated, in order to maintain civil order Oldenbarnevelt eventually proposed that local authorities be given the power to raise troops (the Sharp Resolution of August 4, 1617). Such a measure undermined the unity of the Republic's military force, the very same reason Spain had managed to retake so much lost territory in the 1580s, something the Captain-General of the republic, Maurice of Nassau, Prince of Orange could not allow with the treaty nearing its end. Maurice seized the opportunity to solidify the preeminence of the Gomarists, whom he had supported, and to eliminate the nuisance he perceived in Oldenbarnevelt (the latter had previously brokered the Twelve Years' Truce with Spain in 1609 against Maurice's wishes). During this time Grotius made another attempt to address ecclesiastical politics by completing De Imperio Summarum Potestatum circa Sacra, on "the relations between the religious and secular authorities...Grotius had even cherished hopes that publication of this book would turn the tide and bring back peace to church and state".[23]

Grotius' escape from Loevestein Castle in 1621

The conflict between Maurice and the States of Holland, led by Oldenbarnevelt and Grotius, about the Sharp Resolution and Holland's refusal to allow a National Synod, came to a head in July 1619 when a majority in the States General authorized Maurice to disband the auxiliary troops in Utrecht. Grotius went on a mission to the States of Utrecht to stiffen their resistance against this move, but Maurice prevailed. The States General then authorized him to arrest Oldenbarnevelt, Grotius and Rombout Hogerbeets on 29 August 1618. They were tried by a court of delegated judges from the States General. Van Oldenbarnevelt was sentenced to death and was beheaded in 1619. Grotius was sentenced to life imprisonment and transferred to Loevestein Castle.[27]

From his imprisonment in Loevestein, Grotius made a written justification of his position "as to my views on the power of the Christian [civil] authorities in ecclesiastical matters, I refer to my...booklet De Pietate Ordinum Hollandiae and especially to an unpublished book De Imperio summarum potestatum circa sacra, where I have treated the matter in more detail...I may summarize my feelings thus: that the [civil] authorities should scrutinize God's Word so thoroughly as to be certain to impose nothing which is against it; if they act in this way, they shall in good conscience have control of the public churches and public worship – but without persecuting those who err from the right way."[23] Because this stripped Church officials of any power some of their members (such as Johannes Althusius in a letter to Lubbertus) declared Grotius' ideas diabolical.[23]

A book chest exhibited at Loevestein, presumed to be that in which Grotius escaped in 1621

In 1621, with the help of his wife and his maidservant, Elsje van Houwening, Grotius managed to escape the castle in a book chest and fled to Paris. In the Netherlands today, he is mainly famous for this daring escape. Both the Rijksmuseum in Amsterdam and the museum Het Prinsenhof in Delft claim to have the original book chest in their collection.[28]

Grotius then fled to Paris, where the authorities granted him an annual royal pension.[29] Grotius lived in France almost continuously from 1621 to 1644. His stay coincides with the period (1624-1642) during which the Cardinal Richelieu led France under the authority of Louis XIII. In France in 1625 Grotius published his most famous book, De jure belli ac pacis [On the Law of War and Peace] dedicated to Louis XIII of France.

While in Paris, Grotius set about rendering into Latin prose a work which he had originally written as Dutch verse in prison, providing rudimentary yet systematic arguments for the truth of Christianity. The Dutch poem, Bewijs van den waren Godsdienst, was published in 1622, the Latin treatise in 1627, under the title De veritate religionis Christianae.

In 1631 he tried to return to Holland, but the authorities remained hostile to him. He moved to Hamburg in 1632. But as early as 1634, the Swedes - a European superpower - sent him to Paris as ambassador. He remained ten years in this position where he had the mission to negotiate for Sweden the end of the Thirty Years War. During this period, he had been interested in the unity of Christians and published many texts that will be grouped under the title of Opera Omnia Theologica.

Title page from the second edition (Amsterdam 1631) of De jure belli ac pacis

Living in the times of the Eighty Years' War between Spain and the Netherlands and the Thirty Years' War between Catholic and Protestant European nations (Catholic France being in the otherwise Protestant camp), it is not surprising that Grotius was deeply concerned with matters of conflicts between nations and religions. His most lasting work, begun in prison and published during his exile in Paris, was a monumental effort to restrain such conflicts on the basis of a broad moral consensus. Grotius wrote:

Fully convinced...that there is a common law among nations, which is valid alike for war and in war, I have had many and weighty reasons for undertaking to write upon the subject. Throughout the Christian world I observed a lack of restraint in relation to war, such as even barbarous races should be ashamed of; I observed that men rush to arms for slight causes, or no cause at all, and that when arms have once been taken up there is no longer any respect for law, divine or human; it is as if, in accordance with a general decree, frenzy had openly been let loose for the committing of all crimes.[31]

De jure belli ac pacis libri tres (On the Law of War and Peace: Three books) was first published in 1625, dedicated to Grotius' current patron, Louis XIII. The treatise advances a system of principles of natural law, which are held to be binding on all people and nations regardless of local custom. The work is divided into three books:

• Book I advances his conception of war and of natural justice, arguing that there are some circumstances in which war is justifiable.
• Book II identifies three 'just causes' for war: self-defense, reparation of injury, and punishment; Grotius considers a wide variety of circumstances under which these rights of war attach and when they do not.
• Book III takes up the question of what rules govern the conduct of war once it has begun; influentially, Grotius argued that all parties to war are bound by such rules, whether their cause is just or not.

• Further information: Temperamenta belli

Engraved portrait of Grotius

Grotius' concept of natural law had a strong impact on the philosophical and theological debates and political developments of the 17th and 18th centuries. Among those he influenced were Samuel Pufendorf and John Locke, and by way of these philosophers his thinking became part of the cultural background of the Glorious Revolution in England and the American Revolution.[32] In Grotius' understanding, nature was not an entity in itself, but God's creation. Therefore, his concept of natural law had a theological foundation.[33] The Old Testament contained moral precepts (e.g. the Decalogue), which Christ confirmed and therefore were still valid. They were useful in interpreting the content of natural law. Both Biblical revelation and natural law originated in God and could therefore not contradict each other.[34]

Many exiled Remonstrants began to return to the Netherlands after the death of Prince Maurice in 1625 when toleration was granted to them. In 1630 they were allowed complete freedom to build and run churches and schools and to live anywhere in Holland. The Remonstrants guided by Johannes Wtenbogaert set up a presbyterial organization. They established a theological seminary at Amsterdam where Grotius came to teach alongside Episcopius, van Limborch, de Courcelles, and Leclerc.

In 1634 Grotius was given the opportunity to serve as Sweden's ambassador to France. Axel Oxenstierna, regent of the successor of the recently deceased Swedish king, Gustavus Adolphus, was keen to have Grotius in his employ. Grotius accepted the offer and took up diplomatic residence in Paris, which remained his home until he was released from his post in 1645.

In 1644, the queen Christine of Sweden, who had become an adult, began to perform her duties and brought him back to Stockholm. During the winter of 1644–1645 he went to Sweden in difficult conditions, which he decided to leave in the summer of 1645.

While departing from his last visit to Sweden, Grotius was shipwrecked on the voyage. He washed up on the shore of Rostock, ill and weather-beaten, and on August 28, 1645, he died; his body at last returned to the country of his youth, being laid to rest in the Nieuwe Kerk in Delft.[35][36]

Syntagma Arateorum

Grotius' personal motto was Ruit hora ("Time is running away"); his last words were purportedly, "By understanding many things, I have accomplished nothing" (Door veel te begrijpen, heb ik niets bereikt).[37] Significant friends and acquaintances of his included the theologian Franciscus Junius, the poet Daniel Heinsius, the philologist Gerhard Johann Vossius, the historian Johannes Meursius, the engineer Simon Stevin, the historian Jacques Auguste de Thou, the Orientalist and Arabic scholar Erpinius, and the French ambassador in the Dutch Republic, Benjamin Aubery du Maurier, who allowed him to use the French diplomatic mail in the first years of his exile. He was also friends with the Brabantian Jesuit Andreas Schottus.[38]

Grotius was the father of regent and diplomat Pieter de Groot.

Marble bas-relief of Hugo Grotius among 23 reliefs of great historical lawgivers in the chamber of the U.S. House of Representatives in the United States Capitol

Annotationes ad Vetus Testamentum (1732)

The Peace Palace Library in The Hague holds the Grotius Collection, which has a large number of books by and about Hugo Grotius. The collection was based on a donation from Martinus Nijhoff of 55 editions of De jure belli ac pacis libri tres.

Works are listed in order of publication, with the exception of works published posthumously or after long delay (estimated composition dates are given).[48][49] Where an English translation is available, the most recently published translation is listed beneath the title.

• Martiani Minei Felicis Capellæ Carthaginiensis viri proconsularis Satyricon, in quo De nuptiis Philologiæ & Mercurij libri duo, & De septem artibus liberalibus libri singulares. Omnes, & emendati, & Notis, siue Februis Hug. Grotii illustrati [The Satyricon by Martianus Minneus Felix Capella, a man from Carthage, which includes the two books of 'On the Marriage of Philology and Mercury', and the book named 'On the Seven Liberal Arts'. Everything, including corrections, annotations as well as deletions and illustrations by Hug. Grotius] - 1599
• Adamus exul (The Exile of Adam; tragedy) – The Hague, 1601
• De republica emendanda (To Improve the Dutch Republic; manuscript 1601) – pub. The Hague, 1984
• Parallelon rerumpublicarum (Comparison of Constitutions; manuscript 1601–02) – pub. Haarlem 1801–03
• De Indis (On the Indies; manuscript 1604–05) – pub. 1868 as De Jure Praedae
• Christus patiens (The Passion of Christ; tragedy) – Leiden, 1608
• Mare Liberum (The Free Seas; from chapter 12 of De Indis) – Leiden, 1609
• De antiquitate reipublicae Batavicae (On the Antiquity of the Batavian Republic) – Leiden, 1610 (An extension of François Vranck's Deduction of 1587 [50])

The Antiquity of the Batavian Republic, ed. Jan Waszink and others (van Gorcum, 2000).

• Meletius (manuscript 1611) – pub. Leiden, 1988

Meletius, ed. G.H.M. Posthumus Meyjes (Brill, 1988).

• Annales et Historiae de rebus Belgicis (Annals and History of the Low Countries' War; manuscript 1612-13) – pub. Amsterdam, 1657

The Annals and History of the Low-Countrey-warrs, ed. Thomas Manley (London, 1665):

Modern Dutch translation of the "Annales" only in: Hugo de Groot, "Kroniek van de Nederlandse Oorlog. De Opstand 1559-1588", ed. Jan Waszink (Nijmegen, Vantilt 2014), with introduction, index, plates.

• Ordinum Hollandiae ac Westfrisiae pietas (The Piety of the States of Holland and Westfriesland) – Leiden, 1613

Ordinum Hollandiae ac Westfrisiae pietas, ed. Edwin Rabbie (Brill, 1995).

• De imperio summarum potestatum circa sacra (On the power of sovereigns concerning religious affairs; manuscript 1614–17) – pub. Paris, 1647

De imperio summarum potestatum circa sacra, ed. Harm-Jan van Dam (Brill, 2001).

• De satisfactione Christi adversus Faustum Socinum (On the satisfaction of Christ against [the doctrines of] Faustus Socinus) – Leiden, 1617

Defensio fidei catholicae de satisfactione Christi, ed. Edwin Rabbie (van Gorcum, 1990).

Grotius, Hugo (1889). A defence of the Catholic faith concerning the satisfaction of Christ against Faustus Socinus (PDF). Andover, MA: W. F. Draper.

• Inleydinge tot de Hollantsche rechtsgeleertheit (Introduction to Dutch Jurisprudence; written in Loevenstein) – pub. The Hague, 1631

The Jurisprudence of Holland, ed. R.W. Lee (Oxford, 1926).

• Bewijs van den waaren godsdienst (Proof of the True Religion; didactic poem) – Rotterdam, 1622
• Apologeticus (Defense of the actions which led to his arrest (This was for a long time the only source for what transpired during Grotius' trial in 1619, because the trial record was not published at the time. However, Robert Fruin edited this trial record in [51]) – Paris, 1922
• De jure belli ac pacis (On the Law of War and Peace) – Paris, 1625 (2nd ed. Amsterdam 1631)

Hugo Grotius: On the Law of War and Peace. Student edn. Ed. Stephen C. Neff (Cambridge: Cambridge University Press, 2012)

• De veritate religionis Christianae (On the Truth of the Christian religion) – Paris, 1627

The Truth of the Christian Religion, ed. John Clarke (Edinburgh, 1819).

• Sophompaneas (Joseph; tragedy) – Amsterdam, 1635
• De origine gentium Americanarum dissertatio (Dissertation of the origin of the American peoples) – Paris 1642
• Via ad pacem ecclesiasticam (The way to religious peace) – Paris, 1642
• Annotationes in Vetus Testamentum (Commentaries on the Old Testament) – Amsterdam, 1644
• Annotationes in Novum Testamentum (Commentaries on the New Testament) – Amsterdam and Paris, 1641–50
• De fato (On Destiny) – Paris, 1648

• Coenraad van Beuningen
• Emer de Vattel
• English school of international relations theory
• International waters
• 9994 Grotius - an asteroid named after Hugo Grotius

See Catalogue of the Grotius Collection (Peace Palace Library, The Hague) and 'Grotius, Hugo' in Dictionary of Seventeenth Century Dutch Philosophers (Thoemmes Press 2003).

• Alvarado, Ruben (2018). The Debate That Changed the West: Grotius versus Althusius. Aalten: Pantocrator Press. ISBN 978-90-76660-51-6. OCLC 1060613096.
• Bayle, Pierre. (1720). "Grotius", in Dictionaire historique et critique, 3rd ed. (Rotterdam: Michel Bohm).
• Bell, Jordy: Hugo Grotius: Historian. Ann Arbor, MI: University Microfilms, 1980
• Blom, Andrew (2016). "Hugo Grotius". Internet Encyclopedia of Philosophy. Retrieved 12 January 2016.
• Blom, H. W.; Winkel, L. C.: Grotius and the Stoa. Van Gorcum Ltd, 2004, 332pp
• Borschberg, Peter, 2011, Hugo Grotius, the Portuguese and Free Trade in the East Indies, Singapore and Leiden: Singapore University Press and KITLV Press.
• Brandt, Reinhard: Eigentumstheorien von Grotius bis Kant (Problemata). Stuttgart-Bad Cannstatt: Frommann-Holzboog, 1974, 275pp
• Brett, Annabel (2 April 2002). "Natural Right and Civil Community: The Civil Philosophy of Hugo Grotius". The Historical Journal. 45 (1): 31–51. doi:10.1017/S0018246X01002102. S2CID 159489997.
• Buckle, Stephen: Natural Law and the Theory of Property: Grotius to Hume. Oxford University Press, USA, 1993, 344pp
• Burigny, Jean Lévesque de: The Life of the Truly Eminent and Learned Hugo Grotius: Containing a Copious and Circumstantial History of the Several Important and Honourable Negotiations in Which He was Employed; Together with a Critical Account of His Works. London: printed for A. Millar, 1754. Also Echo Library, 2006.
• Butler, Charles: The Life of Hugo Grotius: With Brief Minutes of the Civil, Ecclesiastical, and Literary History of the Netherlands. London: John Murray, 1826.
• Chappell, Vere: Grotius to Gassendi (Essays on Early Modern Philosophers). Garland Publishing Inc, New York, 1992, 302pp
• Craig, William Lane (1985). The Historical Argument for the Resurrection of Christ During the Deist Controversy. Lewiston: Edwin Mellen Press.
• Dulles, Avery (1999). A History of Apologetics. Eugene, Oregon: Wipf & Stock.
• Dumbauld, Edward, 1969. The Life and Legal Writings of Hugo Grotius. Norman, OK: University of Oklahoma Press.
• Edwards, Charles S., 1981. Hugo Grotius, The Miracle of Holland: A Study in Political and Legal Thought. Chicago: Nelson Hall.
• Falk, Richard A.; Kratochwil, Friedrich; Mendlovitz, Saul H.: International Law: A Contemporary Perspective (Studies on a Just World Order, No 2). Westview Press, 1985, 702pp
• Feenstra, Robert; Vervliet, Jeroen: Hugo Grotius: Mare Liberum (1609–2009). BRILL, 2009, 178pp
• Figgis, John Neville: Studies of Political Thought from Gerson to Grotius 1414–1625. Cambridge University Press, 1907, 258pp
• Gellinek, Christian: Hugo Grotius (Twayne's World Authors Series). Twayne Publishers Inc., Boston, U.S., 1986, 161pp
• Grotiana. Assen, The Netherlands: Royal Van Gorcum Publishers. A journal of Grotius studies, 1980–.
• Gurvitch, G. (1927). La philosophie du droit de Hugo Grotius et la théorie moderne du droit international,. Revue de Metaphysique et de Morale, vol. 34: 365–391.
• Haakonssen, Knud: Natural Law and Moral Philosophy: From Grotius to the Scottish Enlightenment. Cambridge University Press, 1996
• Haakonssen, Knud (19 August 2016). "Hugo Grotius and the History of Political Thought". Political Theory. 13 (2): 239–265. doi:10.1177/0090591785013002005. S2CID 144743124.
• Haggenmacher, Peter (1983). Grotius et la doctrine de la guerre juste (in French). Paris: Presses Universitaires de France.
• Haskell, John D.: Hugo Grotius in the Contemporary Memory of International Law: Secularism, Liberalism, and the Politics of Restatement and Denial. (Emory International Law Review, Vol. 25, No. 1, 2011), H. Grotius in the Contemporary Memory of Intl. Law: Secularism, Liberalism, & the Politics of Restatement & Denial
• Heering, Jan-Paul: Hugo Grotius As Apologist for the Christian Religion: A Study of His Work De Veritate Religionis Christianae, 1640 (Studies in the History of Christian Thought). Brill Academic, 2004, 304pp
• Jeffery, Renée: Hugo Grotius in International Thought (Palgrave MacMillan History of International Thought). Palgrave Macmillan, 1st edition, 2006, 224pp
• Keene, Edward: Beyond the Anarchical Society: Grotius, Colonialism and Order in World Politics. Port Chester, N.Y.: Cambridge University Press, 2002
• Kingsbury, Benedict: A Grotian Tradition of Theory and Practice?: Grotius, Law, and Moral Skepticism in the Thought of Hedley Bull. (Quinnipiac Law Review, No.17, 1997)
• Knight, W.S.M., 1925. The Life and Works of Hugo Grotius. London: Sweet & Maxwell, Ltd.
• Kowalski, Klaus (2022). Das Vertragsverständnis des Hugo Grotius. Zwischen Gerechtigkeit, Treue und Rechtsübertragung. Cologne: Böhlau. doi:10.7788/9783412524944. ISBN 978-3-412-52492-0. S2CID 248843705.
• Lauterpacht, Hersch, 1946, "The Grotian Tradition in International Law," in British Yearbook of International Law.
• Leger, James. St. (1962). The 'Etiamsi Daremus' of Hugo Grotius: A Study in the Origins of International Law (Rome: Pontificium Athenaeum Internationale).
• Li, Hansong (2019). "Time, right and the justice of war and peace in Hugo Grotius's political thought". History of European Ideas. 45 (4): 536–552. doi:10.1080/01916599.2018.1559750. S2CID 149954929.
• Mattei, Jean Mathieu (2006). Histoire du droit de la guerre (1700-1819), Introduction à l'histoire du droit international, avec une biographie des principaux auteurs de la doctrine de l'antiquité à nos jours (in French). Aix en Provence: Presses universitaires d'Aix en Provence.
• Mühlegger, Florian. Hugo Grotius. Ein christlicher Humanist in politischer Verantwortung. Berlin and New York, de Gruyter, 2007, XIV, 546 S. (Arbeiten zur Kirchengeschichte, 103).
• Neff, Stephen C.: Hugo Grotius On the Law of War and Peace: Student Edition. Cambridge University Press, 2012, 546pp
• Nellen, Henk J. M., 2007. Hugo de Groot: Een leven in strijd om de vrede (official Dutch State biography). The Hague: Balans Publishing.
• ——— and Rabbie, eds., 1994. Hugo Grotius, Theologian. New York: E.J. Brill.
• O'Donovan, Oliver. 2004. "The Justice of Assignment and Subjective Rights in Grotius," in Bonds of Imperfection: Christian Politics Past and Present.
• O'Donovan, Oliver; O'Donovan, Joan Lockwood: From Irenaeus to Grotius: A Sourcebook in Christian Political Thought. Wm. B. Eerdmans Publishing Company, 1999, 858pp
• Onuma, Yasuaki (ed.): A Normative Approach to War: Peace, War, and Justice in Hugo Grotius. Oxford: Clarendon Press, 1993, 421pp
• Osgood, Samuel: Hugo Grotius and the Arminians. Hila, MT: Kessinger Pub., 2007
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Wikisource has original works by or about:
Hugo Grotius

Collections

• Works by Hugo Grotius at Project Gutenberg
• Works by or about Hugo Grotius at Internet Archive
• Works by Hugo Grotius at LibriVox (public domain audiobooks)
• Works by Hugo Grotius at Post-Reformation Digital Library
• Works by Hugo Grotius in Short Title Catalogue Netherlands (STCN)

Individual works by Grotius

• On the Laws of War and Peace (abridged)
• On the Laws of War and Peace (Latin, first edition 1625)
• Logicarum disputationum quarta de postpraedicamentis; disputation, aged 14, at Leiden University
• Physicarum disputationum septima de infinito, loco et vacuo; disputation, aged 14, at Leiden University

Other

• Extensive catalogue of Grotius' writings at the Peace Palace Library, The Hague. Unfortunately, this links leads to: "Forbidden. You don't have permission to access /files/Grotius_Collection.pdf on this server."
• The Correspondence of Hugo de Groot (Grotius) in EMLO
• Blom, Andrew. "Hugo Grotius". Internet Encyclopedia of Philosophy.
• Miller, Jon. "Hugo Grotius". In Zalta, Edward N. (ed.). Stanford Encyclopedia of Philosophy.
• Hugo Grotius' Quotes