The foundations of modern international law lay on the moral critique of the Spanish empire made by the sixteenth-century Dominican Friar and Professor of Theology, Francisco de Vitoria. While Hugo Grotius is generally considered the father of international law, historians of the discipline trace its primitive origins to the works of Vitoria. 
Most striking is the fact that the works of Vitoria, “whose long shadow extends,” according to Anthony Padgen, “over all subsequent discussions over the Law of Peoples,”  are not a body of writings elaborated by Vitoria himself. In fact, Vitoria never published during his lifetime. His works were perpetuated in the form of notes taken down by his students during his relectiones (the lectures given in Salamanca at the end of each university term). In total, Vitoria offered fifteen lectures, of which thirteen are preserved. Six are regarded as fundamental. His first four lectures, between the years 1528 and 1534,  addressed the thorny issue of relations between the civil and ecclesiastical powers, the two great powers of the time. Yet, it is in ‘De Indis Recenter Inventis’ of 1538 and ‘De Indis sive de Iure Belli Hispanorum in Barbaros”  of 1539, that scholars see early expressions of the doctrine of international law. This essay reviews Vitoria’s De Indis lectures.
Born in Burgos in 1483, Francisco de Vitoria entered the Order of Preachers and finished studies at the University of Paris. It was during his time in Paris where he was widely influenced by the work of the French humanists of his epoch and, above all, by St. Thomas Aquinas and Aquinas’s attempt to reconcile Greek philosophy and Holy writ. Vitoria taught for 20 years at the University of Salamanca and is regarded as the leader of the scholastic revival, commonly known as the School of Salamanca. His idea of an universal international legal order valid for all peoples evolved from the work of St. Thomas of Aquinas and St. Augustine’s conception of the family of peoples, understood both as a community of states and as a community of men.
At a time when looting, pillage, exploitation and conquest were common in the territories discovered by Spain, Vitoria attempted to enunciate, from the theology of ethics, a universal system of laws ruling all mankind. For Vitoria was not only inspired by the plight of the Indians under Spanish colonial rule, but also by his struggles with the theological implications of natural law theory, a struggle which can be observed in his lectures on ecclesiastical power. Indeed, for theologians like Vitoria, secular and ecclesiastical power were intricately linked, thus theories postulated in one domain had implications in the other.
More than four decades had passed since the arrival of Columbus at Hispanola in 1492 when Vitoria delivered his De Indis lectures, and by then the excesses of the Spanish in their newly conquered territories were well known. In De Indis, Vitoria is essentially concerned with relations between the Spanish and the Indians, and his jurisprudence is built around his attempts to resolve the unique legal problems arising from the discovery of the Americas. The fundamental point is that the law, such as it existed in the sixteenth century, did not resolve the problem of Spanish-Indians relations.
Vitoria undertakes to answer several questions, including: By what right did the Indians come under the sway of the Spanish? What is the extent of the temporal and civil power of Spain over the Indians? Are Christians allowed to wage war? With whom rests the authority to declare war and when is a war just? It could be argued that Vitoria’s answers to these questions are less significant than his method at arriving at them. Vitoria’s method of discussion is one known as the scholastic method, established by St Thomas Aquinas. Indeed, Vitoria’s argument advances by syllogisms, which are used not merely to prove his opinions, but in a preliminary dissertation, to prove the points opposed to his own. Thus, the syllogisms themselves are constructed on the basis of authority, and here we observe the working of Victoria’s mind.
In De Indis, Vitoria begins by stating some general ideas about man. He argues that every man (Spanish or Indian), for possessing reason and language, has the right to belong to a fair ethical society. This idea was a novelty for a society that largely considered the Indians as barbarians or childlike. For Vitoria, reason is the foundation of law; where there is reason, there can and must be law; irrational creatures are not responsible. However, rational creatures are responsible. And as Vitoria points out with sharp irony, “also among ourselves we observe rustic people, no different than animals,” because they have not developed their reason or have guided it toward evil. His argument continues by stating that all rational men are responsible for their actions. This means that every man, whether Spanish or Indian, should have equal dignity by virtue of his reason. Moreover, rational beings have responsibility over irrational ones and should use their rational power to care for them, not to dominate them indiscriminately.
Vitoria acknowledges and criticizes the traditional forms of accounting for relations between the Spanish and the Indians, which was decided by applying to the Indian the theory of law developed by the Holy Roman Church to deal with the Saracens (a generic term for Muslims widely used among Christian writers in Europe during the later medieval era). The traditional theory of law that Vitoria criticizes in De Indis relies on two premises: one, that human relations are ruled by divine law; and two, that the Pope exercises universal jurisdiction by virtue of his divine mission to spread the Christian gospel. Thus, following the traditional framework, it is legitimate for a European sovereign to expand Christianity by military conquest if such mission is sanctioned by the head of the Church.
Vitoria strongly refutes these premises and in the course of denying the traditional basis for Spanish rights over the Indians, he constructs a system of law which displaces divine law and its administrator, the Pope, and replaces it with natural law administered by a secular sovereign. Consequently, the development of a universal system of law arises as Vitoria finds a resolution to the problem of the legal status of the Indians.
Vitoria begins his inquiry by addressing the question of whether the Indians, before the arrival of the Spanish, had true dominion (ownership) in both public and private law. He dismisses the argument that Indians lacked ownership simply because of their status as sinners or unbelievers and reframes the relationship between divine, natural and human law. Vitoria takes Aquinas’s conclusion that “it is no impediment for a man to be a true master, that he is an unbeliever,” and argues that “Aquinas shows that unbelief does not cancel either natural or human law, but all forms of dominion derive from natural or human law; therefore they cannot be annulled by lack of faith.” Vitoria’s argument, that ownership and property are decided by natural or human law rather than by divine law, inexorably lessens the power of the Church.
Vitoria goes on to refute another justification for the Spanish conquest, one which further diminishes the position of the Pope. He questions whether divine law could provide the basis for temporal authority and concludes that the Pope is not civil or temporal lord of the whole world and that his authority is limited to the spiritual dimension of the Christian world. All power, Vitoria explains in De Indis, comes from God, and natural law respects the exercise of civil authority. No temporal society, which exists for the common good, can claim power over another temporal society. He then concludes that neither is the Spanish emperor master of the whole world, because dominion can exist only by natural law, divine law or human law, and the emperor is not master of the world by any of these.
The resolution of this issue is vital for Vitoria’s creation of a legal framework which would enable him to resolve the problem of the status of the Indians. Vitoria addresses the issue of jurisdiction by looking at two interconnected parts. First, he looks at the issue of Indian personality and rejects the description of Indians as being sinners, lunatics, minors and animals. He concludes that the Indians possess the necessary reason not only to create institutions, but also to determine moral questions. Second, he argues that “what natural reason has established among all nations is called jus gentium,” the law of nations. As a result, and precisely because the Indians possess reason, they are bound by jus gentium. Thus, the issue of jurisdiction is resolved by the enunciation of this concept; divine law is replaced by a universal natural law system, whose rules may be determined by the use of reason. Vitoria argues that the natural law, which solves the problem of jurisdiction, is based on a state of nature “permissible from the beginning of the world,” by which a universal system to travel, trade and settle is legitimized. Thus, the particular practices of the Spanish are presented as universal, as a result of appearing to derive from the sphere of natural law. The Indians participate in this system as equals, because they possess the same character as the Spanish (they possess reason and hence a means of ascertaining jus gentium). This is an essential prerequisite for Vitoria’s construction of a universal system of law, which he presents as founded upon qualities possessed by all people. However, the Indians are very different from the Spanish because the Indians’ cultural practices are in disagreement with the practices required by the universal system of law, which in effect reflect Spanish social and cultural practices and which are applicable to all. Consequently, the Indians possess the potential to perfection and this potential can only be realized by the adoption of the universally applicable practices of the Spanish. According to Vitoria, the “law of nations” is a set of principles enacted by the power of “the whole world, which is a sense of commonwealth” regardless of the particularities of each community around the world.
This point takes as to a central issue in De Indis: that of war, and with it an apparent turn in Vitoria’s argument. War is essential in Vitoria’s work because Vitoria’s concept of sovereignty is elaborated mainly in terms of the sovereign’s right to wage war. As Vitoria constructs a law of nations, administered by the sovereign, he reintroduces Christian norms as universal rules endorsed by jus gentium. Evangelizing is authorized not by divine law but by the law of nations, and may be likened now to travelling and trading. Vitoria argues that “…ambassadors are inviolable in the law of nations (jus gentium). The Spanish are the ambassadors of Christendom, and hence the barbarians are obliged at least a fair hearing and not expel them.”
Thus, acceptance of the Christian faith could not be forced and should not serve as an excuse for conquest. Even if the Indians were guilty of sins against nature, or were “incapable” of self-rule, still, because sin did not deny one’s human right to own things, conquest and rule under a foreign power could not be forced. On the other hand, Vitoria states that no one could ban the effort to preach the Christian gospel and evangelize. The missionaries, with their converts, had the right to invoke protection against non-converts.
In this context, Vitoria elaborates on the situations in which war is justified: “ Once the Spaniards have demonstrated diligently both in word and deed that for their own part they have every intention of letting the barbarians carry on in peaceful and undisturbed enjoyment of their property, if the barbarians nevertheless persist in their wickedness and strive to destroy the Spaniards, they may then treat them no longer as innocent enemies, but as treacherous foes against whom all rights of war can be exercised. . . . All this must be done in moderation, in proportion to the actual offence.”
To summarize briefly the background of Vitoria’s analysis: Just war theory is an essential aspect of the laws of war, as the sovereign is entitled to go to war only in certain circumstances. Indeed, it was Cicero who first articulated a just war theory in his writings,which were further developed by St. Augustine of Hippo and St. Thomas Aquinas. Vitoria takes just war theory and adapts it to the new conditions created by the Spanish discovery of the new world.
The first four centuries of the Church indicate two streams of thought, one rejecting violence under any conditions; and the other accepting the need for just defense and military service. It is with Augustine that the beginnings of a theory of morally legitimate use of force emerged, even though he did not enumerate the conditions necessary for a war to be just. Augustine fashioned his ideas amidst the violence and disorder in the Roman Empire and claimed that defense of one’s self or others could be a necessity, especially when authorized by a legitimate authority. In the 13th century, St. Thomas Aquinas used the authority of Augustine’s arguments to refined the just war tradition in order to provide clarity. Aquinas laid out the criteria under which a war could be just. He used a passage from the Psalms (“Rescue the poor: and deliver the needy out of the hand of the sinner” Ps. 82:4) to justify the obligation of Christian princes to stand up for the rights of Christians beyond the reach of the Christian jurisdiction if these Christians are unable to receive any legal protection from authorities directly in charge: “In order for a war to be just, three things are necessary. First, the authority of the sovereign by whose command the war is to be waged, for it is not the business of a private individual to declare war, because he can seek for redress of his rights from the tribunal of his superior. Secondly, a just cause is required, namely that those who are attacked should be attacked because they deserve it on account of some fault. Thirdly, it is necessary that the belligerents should have a rightful intention, so that they intend the advancement of good, or the avoidance of evil.”
In De Indis, Vitoria expands on Thomistic understanding of just war, in the context of the social and geopolitical circumstances of his time. He reasons that, given that war is one of the worst evils suffered by mankind, it ought to be resorted to only when it is necessary in order to prevent an even greater evil. A war must comply with a series of additional requirements in order to be legitimate: It is necessary that the response be commensurate to the evil; that a legitimate authority declares war; and that once war has begun, there remain moral limits to action. Vitoria rejects the argument that subjective belief in the justness of a war would suffice to make it just because “were it otherwise, even Turks and Saracens might wage just wars against Christians, for they think they are thus rendering God service.” Vitoria arrives at this conclusion by establishing the premise that “the Saracens are inherently incapable of waging a just war.”
By establishing this exclusion and extending it to the Indians, Vitoria concludes that only Christians may engage in a just war and, given Vitoria’s argument that the power to wage war is the most important prerogative of sovereigns, it follows that the Indians can never be truly sovereign. Thus the Indians exist only as objects against which to exercise the power to wage war, for “. . . and this is especially the case against the unbeliever, from whom it is useless ever to hope for a just peace on any terms. And as the only remedy is to destroy all of them who can bear arms against us, provided they have already been in fault.” Vitoria bases his conclusion, that the Indians are not sovereign, on the simple assertion that they are pagans. Even though the Indians are men, they are still “barbaric” because of “their evil and barbarous education.” Among the signs of barbarism, cannibalism and human sacrifice are the most unnatural and, according to Vitoria, military intervention may be justified by the universal right to defend the innocent, even against their will. The Indians, possessing universal reason and yet barbaric, are subject to sanctions because of their failure to abide by universal norms.
Vitoria’s reasoning on just war, as applied to the Indians, apparently stands in stark contrast with his previously-held conclusions about the humanity of the natives of the New World. Indeed, he resorts to the same argument he refuted when denying the validity of the Church’s claims, that the Indians lacked rights under divine law because they were pagans. Vitoria’s argumentation is nonetheless consistent: the Indians who violate jus gentium are denied the status of sovereign. And thus, the consequence of Vitoria’s thought is clear: for the Indians to be free and the legal owner of their land, as well as capable of reaching salvation, they must become subjects of the Spanish crown.
Indeed, Vitoria emerges as both a critic of a rising power political order and as a theological theorist dedicated to restructuring and adjusting the previous system of theology in accordance with the new political and religious environment. Vitoria knows he is attempting to construct a new theological system and in fact in the introduction to De Indis he says “it may first of all be objected that this whole dispute is unprofitable and fatuous.” Given the intensely religious foundations of Spanish society and culture at the time, his arguments are especially bold and marked Vitoria as a radical thinker. However, the practical thrust of his arguments seem to be supportive of the status quo, with respect to the Spanish empire at least, whatever humanizing elements he may have sought to encourage.
The alleged role of Vitoria in ultimately justifying the Spanish conquest in his De Indis has prompted much debate among scholars, particularly those of the “Third World” approach.  The political theorist and jurist Carl Schmitt’s argued that we have been misled by Vitoria’s impartiality and his belief that the conquest was unjust, when his conclusions ultimately justifies the conquest. Teofilo Urdanoz, the Spanish Vitoria scholar, argues that Vitoria’s De Indis creates a “new entity” or “new reality,” within which the Indian would be constructed and that this construction responds directly to the institutional need to legitimize the colonization. Some scholars, including Anthony Padgen, have attributed to Vitoria the articulation of a conception of natural law that presumably served to place non-Christians in a position of inferiority and subservience. Others have argued that Vitoria was a humanist interested in geographic and commercial expansion more than in the Indian.
Vitoria may have only been motivated by the possibility of integrating the diversity of theological and juridical systems into an all-encompassing corpus of doctrine, to construct a coherent system in changing political circumstances. However, Vitoria’s ideas not only defined the key elements for a new theological theory, one that preserved both the rights of the Indians and those of the Spanish Crown, but also simultaneously provided a justification for the Spanish intervention in the New World. One possible explanation may be that, in the end, Vitoria was attempting to provide a synthesis of a balanced theological system which could explain and justify Spanish colonization, while introducing elements of humanity, as far as his time and circumstances would allow. Certainly, at no point in De Indis does he advocate a Spanish departure from the New World.
We might note a related point. Vitoria is associated with the two branches of the laws of war: the jus ad bellum and the jus in bello. Consequently, modern notions of humanitarian intervention have been re-traced back to the “duties towards the defense of the innocent,” which Vitoria signals in De Indis as one of the possible causes for a just war. Indeed, the implicit assessment that jus gentium does not admit all types of war, but only those linked with the reparation of the received injury, is one of the legacies of Vitoria’s work.
Spain was the political, economic and cultural epicenter of the world during the sixteenth century, and at the time the Spanish regarded themselves as superior and entitled to conquer the world. Vitoria was above all a catholic theologian and his ideas had to serve Christ’s message and more generally, the mission of the Church. Vitoria’s work addresses the controversy generated by “the barbarians of the New World, commonly called Indians, who came under the power of the Spaniards forty years ago, having being previously unknown to our world,” He reasons that traditional understandings of law are inadequate to deal with such novel circumstances. In De Indis, Vitoria defends the rights of the Indians while simultaneously laying out rules for Spanish trade, the evangelization of the Americas, and the conduct of war. Indeed, he stood at a particularly significant juncture in the history of political thought, and the position he carefully articulated shows the distinction between secular and spiritual power, a feature that distinguishes modern from medieval thought. And in doing so, he frees the way for the construction of a new, secular, law of nations.
Vitoria’s ideas were fundamental in providing answers to the debates generated by the experience of the Spanish in the Americas, and consequently to the policies that the Spanish Crown took thereafter. He was an immensely popular professor in his time, and his opinion was so well respected that it was sought by King Charles V, the Holy Roman Emperor and King of Spain. From the 1530s, historical accounts note that the Spanish King traded letters with the Salamanca scholars and with Vitoria, making specific inquiries about the evangelization of the Indians in the Americas. It is striking to what extent this theologian was able to debate and challenge the policies of the time.
Up until then, the Laws of Burgos of 1512 had provided the first set of laws governing the behavior of the Spanish in the Americas. The laws prohibited the maltreatment of the Indians and endorsed their conversion to Catholicism. However, the laws were poorly applied and were seen simply as a legalization of the previous poor situation. The Spanish Crown claimed for itself the right to conquer and rule by reason of prior discovery and occupation. The Spanish were in the practice of invoking in their Americas conquests the so-called “Requerimiento,” a document read to the Indians before the beginning of any hostilities. The Requerimiento declared the universal authority of the Pope and the authority the Spanish kings had received from the Pope over the New World. The Indians had to accept the sovereignty of the Spanish monarchs or be compelled to submit by force. Francisco de Vitoria denied the legitimacy of this document.
Vitoria’s influence is visible in the momentum for reform that arose in the years prior to the “New Laws for the Good Treatment and the Preservation of the Indians” of 1542. The New Laws would ultimately drop the Requerimiento. The four hundred years of Spanish presence in the Americas and the Philippines would witness the enactment and application of several sets of the laws. The New Laws of 1542 would be revised in 1552, followed by ordinances, prohibiting unauthorized interventions against independent Indians. First signed in 1573, the Laws of the Indies are considered the first guidelines towards the design and development of communities in the colonies. Thus, to Vitoria is due a good portion of the credit for whatever humanizing effects these laws had on Spanish colonial legislation and on the ethics of warfare.
In 1976, then King Juan Carlos of Spain presented a bronze bust of the Dominican fray to the United Nations Organization, as a memorial of the man who established the foundations of international law. Indeed he did, and he would be an important influence on those how came after him, especially Hugo Grotius.
 For accounts of Vitoria’s place in the discipline of international law, see James Brown Scott, The Spanish Origin of International Law (Oxford: Clarendon: London: H. Milford, 1934). Return to text
 See Anthony Padgen, “Gentili, Vitoria and the Fabrication of a Natural Law of Nations”, in B. Kingsbury and B. Straussman (eds), Roman Foundations of the Law of Nations: Alberico Gentili and the Justice of Empire, (New York: Oxford University Press, 2010) p. 342. Return to text
 The first was ‘De potestate civili,’ followed by ‘De potestate prior Ecclesiae’ in 1532, ‘De potestate back Ecclesiae’ in 1533 and ‘De potestate Papae et Concilii’ in 1534. Return to text
 The titles of the two lectures may be translated as “On the American Indians lately Discovered” (On the American Indians) and “On the Law of War Made by the Spaniards on the Barbarians.” See Anthony Pagden and Jeremy Lawrance (eds.), Francisco de Vitoria: Political Writings (Cambridge: Cambridge University Press, 1991). The two lectures are closely linked: Vitoria makes this point explicitly, that the second lecture is to be considered as a continuation of the first lecture – thus this essay treats them as a single classic and are referred simply as “De Indis”. Return to text
 The School of Salamanca refers to a group of scholars of natural law and of morality who undertook the reconciliation of the teachings of Thomas Aquinas with the new political-economic order of sixteenth century Europe. Return to text
 Antonio Truyol Serra, “El derecho de gentes como orden universal”, in A. Mangas Martín (ed). La escuela de Salamanca y el Derecho Internacional en América: del pasado al futuro (Salamanca, 1993), pp. 24-25. Return to text
 Vitoria’s starting point is St. Thomas Aquinas’s framework, where eternal law is the transposition of the mind of God as seen by God himself; divine law is derived from eternal law as it appears historically to humans, especially through revelation; and natural law is “the participation in the eternal law by rational creatures” (the first part is constituted by the so-called ‘first principles’ that all rational beings are supposed to recognize. From these first principles, a set of secondary or even tertiary ones are derived from and provide the rational foundation for all codified laws). With the Thomist concept of natural law defined by Vitoria, natural law is nothing more than the human contribution to eternal law. Return to text
 Roland Kany, “Augustine’s Theology of Peace and the Beginning of the Christian Just War Theory,” in Heinz-Gerhard Justenhoven and William A. Barbieri, Jr. (eds), From Just War to Modern Peace Ethics (Berlin: De Gruyter, 2012), 31. Return to text
 In his work Summa Theologica. Return to text
 See Antony Anghie, “The Evolution of International Law: Colonial and Postcolonial Realities,” 5 Third World Quarterly (2006). Return to text
 For example, scholars belonging to the Third World Approaches to International Law School, a School that has led the re-reading of the role of Vitoria in the creation of the legal discourse in the context of the Spanish conquest. See, Anthony Padgen, The Preservation of Order: The School of Salamanca and the Ius Natural in the Uncertainties of Empire, Essays in Iberian and Iberian-American Intellectual History (Aldershot: Varorium, 1994). Anthony Anghie contends that since Vitoria, international law has had the primary function of defining the relationship between Europeans and non-Europeans in the context of colonialism in the first place. See, Antony Anghi, Imperialism, Sovereignty and the Making of International Law, (Cambridge University Press: 2007). Return to text
 Carl Schmitt, The Land Appropriation of the New World (Telos Press, no.109, 1996). Return to text
 Id. 55. Return to text
 Teofilo Urdanoz, Obras de Francisco de Vitoria, (Madrid: Editorial Católica, 1960), 46. Return to text
 See Martti Koskennniemi, “Empire and International Law: The Real Spanish Contribution,” 61 University of Toronto Law Journal (2011), 32. Return to text
For Further Reading
Vitoria, Francisco de. Political Writings. Ed. Anthony Padgen and Jeremy Lawrance (Cambridge: Cambridge University Press, 1991)
Commentaries on Vitoria
Hamilton, Bernice. Political Thought in Sixteenth-Century Spain: A Study of the Political Ideas of Vitoria, De Soto, Suarez and Molina (Oxford: Clarendon Press, 1963)
Urdanoz, Teofilo, Obras de Francisco de Vitoria. (Madrid: Editorial Catolica, 1960)
Scott, James Brown, The Spanish Origin of International Law (Oxford: H. Milford, 1934)
Williams, Robert A. Jr. The American Indian in Western Legal Thought: The Discourses of Conquest (New York: Oxford University Press, 1990)
On the History of the Spanish Empire
Hanke, Lewis. The Spanish Struggle for Justice in the Conquest of America (Southern Methodist University Press, 2002)
Mc Alister, Lyle N. Spain and Portugal in the New World 1492-1700 (Minneapolis: University of Minnesota Press, 1984)
Muldoon, James. The Americas in the Spanish World Order (Philadelphia: U. of Pennsylvania Press, 1994)
Padgen, Anthony. Lords of All the World: Ideologies of Empire in Spain, Britain and France c.1500-c.1800 (New Haven, CT: Yale University Press, 1995)
On the Law of Nations
Muldoon, James. Canon Law, The Expansion of Europe and World Order (Ashgate, 1998)
Neff, Stephen C. War and the Law of Nations: A General History (Cambridge: Cambridge University Press, 2008)
Nussbaum, Arthur. A Concise History of the Law of Nations (New York: Macmillan, 1954)
Padgen, Anthony. The Languages of Political Theory in Early Modern Europe (Cambridge: Cambridge University Press, 1987)