Traditional requirements for statehood

In the aftermath of the Peace of Westphalia of 1648, the requirements for state sovereignty were effective control over a territory, a permanent population, and a government.Footnote ⁸ Looking at accounts of the social and political structures of sub-Saharan African societies at the time, they typically appear to have met those requirements. Contemporary ethnological scholars and historians classify these societies as monarchies with well-established political structures.Footnote ⁹ Ojo/Ekhator, for example, contend that Benin’s legal framework at the time was “[…] well thought out, practicable, and immensely useful in the consolidation of peace […].”Footnote ¹⁰ Similar descriptions were given by early explorers such as Olfert Dapper, a Dutch geographer and historian. In 1670 he wrote on the historic Kingdom of Benin, reporting on architecture comparable to European citiesFootnote ¹¹ and complex social hierarchies with provincial rulers subordinate to the king.Footnote ¹² As another example, Thomas Edward Bowdich, an explorer of the African Company of Merchants, wrote about the Ashantee court in 1817. He compared the kingdom’s political structure to European constitutions, concluding that it implemented an effective separation of powers.Footnote ¹³ Monarchic rule was often legitimized based on dynastic or divine origin, as was the case in Europe at the time.Footnote ¹⁴ Wallace-Bruce, writing specifically on the question of statehood, concludes that “it is palpably clear that Africa had various independent states on the eve of colonialism.”Footnote ¹⁵

The standard of civilization

Despite meeting the traditional requirements for statehood, African states were consistently denied international legal personality and statehood. This was in part based on the argument that they were at a lower level of civilization.Footnote ¹⁶ Whilst disregarding traditional criteria for statehood, racial stereotypes were used to reinterpret idiosyncratic cultural expression in art, religion, and broader culture, defined as the decisive metrics. Tzouvala sees a combination of a “logic of biology,” which characterized Africans as less adaptable, and a “logic of improvement,” which asserted that they needed education.Footnote ¹⁷ From the perspective of third-world approaches to international law (TWAIL), the criteria of civilization represent a central aspect of horizontal inequality in international law, which exerts its effects today.Footnote ¹⁸ However, a closer analysis of the legal term of civilization shows that a shift in interpretation had taken place and that the colonialist’s emphasis on cultural expression as the decisive criterium deviates from the original concept. In its early modern meaning, it denoted a universal ethical standard for all states to act civilized. The concept did not focus on the cultural expressions of a society but posed a set of universal ethical norms. For example, Vattel defines any aggressive state that neglects the rules of just war as savage and uncivilized.Footnote ¹⁹ Grotius even argues that the opponent’s cultural expressions are irrelevant in international affairs: “Therefore it was unjust on the part of the Greeks to say, that the Barbarians were their natural enemies, merely on account of the diversity of manners, or because they seemed to be inferior in intellect.”Footnote ²⁰ Much later, Bluntschli, who certainly supported the superiority of Western states, sometimes argued that cultural differences had no place in international law and that the aggressor was the uncivilized actor: “the war of destruction against the godless peoples of Palestine, […] is considered barbarous in the humane legal thinking of today’s world.”Footnote ²¹ For some, the adherence to such universal ethical norms was even linked to the legitimacy of a state. In this sense, Lormier argued in 1884 that the “measure of ethical life” […] “characterizes civilization,” to then conclude that if a state “ceases to be a State ethically, it ceases to be a State altogether.”Footnote ²²

Accordingly, instead of arguing that the standard of civilization was introduced to legitimize colonialism,Footnote ²³ it seems more accurate to say that colonialist scholars tried to transform the norm to suit their colonial aspirations. They shifted the emphasis of the universal ethical norm to cultural forms of expression and technological knowledge. At the same, they did not shy away from raising ethical arguments as a pretext for interventions and conquest, in particular, regarding the continuation of the slave trade in Africa. Whilst Western scholars criticized African States for the practice, they failed to note that Western powers not only had created the transatlantic slave trade but had taken considerable time to abolish it. In the colonies of the British Empire, slavery persisted until the conclusion of the apprenticeship system under the Emancipation Act of 1838.Footnote ²⁴ France abolished the slave trade in their colonies only in 1848, while in Brazil, it endured until 1888.Footnote ²⁵ Germany, on the other hand, never fully abolished slavery in its colonies until it lost control over them in the early nineteenth century.Footnote ²⁶ Moreover, taking violations of human rights under continuing colonial rule into account, the uncivilized behavior of Western States lasted well into the twentieth century. Despite the perpetuation of slavery and oppression to a certain degree, the Western states considered themselves to be civilized nations. Nevertheless, in order to still be able to exclude sub-Saharan African societies from the international order, scholars ultimately had to place cultural expression above ethical conduct. Reference to unethical conduct was merely used as a façade to enforce a discriminatory doctrine.Footnote ²⁷

Recognition of statehood

Legal positivists also argued that African societies could only achieve statehood or international legal personality through recognition by Western states.Footnote ²⁸ This position infers that recognition replaces all other criteria for statehood. In practice, however, statehood rarely depends on recognition alone – it rather follows social realities. Historical analysis also shows that nineteenth-century scholars considered both the classical criteria as well as recognition in their assessments,Footnote ²⁹ which indicates that the concepts of sovereignty, international legal personality, and statehood were not coherent during that period.Footnote ³⁰ It is also telling that the element of recognition had not been considered as an indispensable requirement under Art. 3 of the Montevideo Convention of 1933. Footnote ³¹

Even if we assumed for a moment that recognition had become the essential criterium under nineteenth-century international law, such a shift could not have invalidated already binding international norms established by practice. Regarding historical African-Western relations, Tzouvala speaks of “alternative forms of international normativity and ordering that had been in operation for centuries both in and beyond Europe.”Footnote ³² African States had longstanding trade and diplomatic relations with Western States,Footnote ³³ which supports their recognition as international legal entities.Footnote ³⁴ Taking this perspective, later protectorate agreements appear as the continuation of existing trade relations in the regions.Footnote ³⁵ Van der Linden points out that African rulers were also actively taking part in the creation of treaties.Footnote ³⁶ Moreover, protectorate agreements were not considered to have dissolved the protected state under nineteenth-century doctrine,Footnote ³⁷ further implying international legal personality.Footnote ³⁸ The arising contradictions then resulted in the denotation of “semi-sovereignty.”Footnote ³⁹ Koskenniemi instead argues that the protectorate was merely chosen as a front to avoid the application of undesired legal norms and to prevent uprisings.Footnote ⁴⁰ In fact, many scholars at the time considered colonial protectorate treaties to be ineffective under international law, arguing they were only promises in the moral sense.Footnote ⁴¹ Consequently, they were not discussed at the Berlin conference.Footnote ⁴² In this regard, both Martin Footnote ⁴³ and Nuzzo Footnote ⁴⁴ point to a further contradiction in the practice of Western states on the international level. If African societies were unable to grant rights in the first place, how could Western states acquire sovereignty and base their territorial claims on these agreements?Footnote ⁴⁵ Art. 34 General Act of the Berlin Conference on West AfricaFootnote ⁴⁶ further proves that these agreements were used by the Western powers to assert their territorial claims and trade privileges.

In order to underpin the argument, we will examine selected English, French, and German protectorate agreements closed with sub-Saharan African rulers. Typically, they did not overtly encroach on internal sovereignty but regulated trade relationships and other aspects of external sovereignty.Footnote ⁴⁷ British agreements repeatedly acknowledged the internal sovereignty of African societies. For example, one agreement refers to “the principal chiefs holding authority on the south Bank of the River Congo.”Footnote ⁴⁸ However, Van der Linden points to the vagueness of the language regarding internal aspects.Footnote ⁴⁹ Sometimes, such agreements granted extensive influence over internal affairs: “The Chiefs […] hereby engage to assist the British Consular or other officers in the execution of such duties as may be assigned to them.”Footnote ⁵⁰ French agreements typically did not extend to the cession of internal sovereignty: “The French Republic will not interfere in the government or in the internal affairs of Baol. The rights of the Teigne (king) and his successors remain absolutely the same as in the past.”Footnote ⁵¹ German agreements also repeatedly left internal sovereignty untouched. The agreement with Mlapa, King of Togo, says the following: “so that [King Mlapa] may be enabled to preserve the independence of his territory. [He] will not cede any part of his country with rights of sovereignty to any foreign power […].”Footnote ⁵²

Besides such agreements closed in the context of trade relations, Western Powers also recognized African states in the aftermath of military campaigns, which illustrates that recognition often followed military realities rather than legal assessments. This was the case when the British recognized Ashanti sovereignty in the Anglo-Ashanti Treaty of Friendship of 1817. Footnote ⁵³ The same accounts for the Treaty of Wuchale of 1889, in which Italy recognized the Ethiopian empire.Footnote ⁵⁴ Western powers also acknowledged sovereignty when they saw no contradiction to their economic and political interests.Footnote ⁵⁵ These scenarios all suggest that sub-Saharan African states were already sovereign beforehand. It had just been the case that they were forced to prove it militarily. This approach ultimately results in the doctrine of the right of the strongest, which is beyond legal argumentation.

In conclusion, given that the traditional criteria for statehood were often fulfilled by African sub-Saharan Societies and that recognition of their sovereignty took place within early trade and protectorate relations as well as after military conflicts, the argument can be made that these societies had been sovereign states. Therefore, both unilateral annexations as well as treaties such as the General Act of the Berlin Conference on West Africa of 1885Footnote ⁵⁶ could not affect their sovereignty. As a second consequence, only those territorial acquisitions or cessions of sovereignty that were based on valid legal agreements could be considered effective.Footnote ⁵⁷ As we have already seen, the protectorate and other colonial treaties generally only provided for the transfer of external sovereignty. However, in order to cover other scenarios, the next chapter will also take unequal treaties in the context of military threats and occupations into account.

Colonial conquest and the just war doctrine

Western powers frequently found themselves dissatisfied with the external control that they gained through protectorate agreements. Consequently, they sought to expand their influence by directly conquering territories or asserting further dominance over internal affairs.Footnote ⁵⁸ Regarding the legal effect of conquest, there were two competing legal doctrines discussed in nineteenth-century scholarship. The first argues for an unconditional right to go to war (liberum ius ad bellum),Footnote ⁵⁹ which is sometimes related to the Hobbesian state of nature paradigm where human interaction unfolds in the absence of any reciprocal rights and obligations.Footnote ⁶⁰ Historically, however, the liberum ius ad bellum typically represented an aspect of internal sovereignty. For example, Bodin introduces the right to wage war in his discussion on internal sovereignty. Only a legitimate ruler could declare war, as opposed to any private undertaking.Footnote ⁶¹ Against this historical background, the nineteenth-century doctrine of liberum ius ad bellum appears to overemphasize a preliminary aspect of internal sovereignty when dealing with the much broader question of the legality of the war. More important, however, is that this reading introduces contradictions into the existing framework. It not only runs against the right to self-determination of other states, but it generally disregards the fundamental peacekeeping function of international law altogether. Simon examined the development of liberum ius ad bellum in detail and came to the conclusion that it never gained enough prominence in state practice and the political discourse to be considered predominant.Footnote ⁶² Instead, he suggests that its relevance had been overstated by twentieth-century legal historians.Footnote ⁶³

The much older bellum iustum doctrine dictates to the contrary, that wars are only lawful in situations of self-help or self-defence. It can be traced back to Roman law,Footnote ⁶⁴ and was later upheld by natural law scholars such as Grotius Footnote ⁶⁵ and Vattel. Footnote ⁶⁶ Simon argues that this principle remained dominant during the nineteenth century.Footnote ⁶⁷ As a central source, he refers to Bluntschli, who wrote that the legitimacy of wars remained a question of international law,Footnote ⁶⁸ rejecting unrestrained acts of war. Simon also describes a “discourse of legitimacy,” which means that wars always had been justified politically throughout the late eighteenth and nineteenth centuries.Footnote ⁶⁹ For example, the French campaign of 1792 had been legitimized as a “just defense of a free people against the aggression of a king.”Footnote ⁷⁰ The same accounts for the political justifications of the Franco-Prussian war of 1871.Footnote ⁷¹ Applying the same rationale, Western powers tried to legitimize their colonial military campaigns based on self-defense. Westlake writes in 1894 that “except in the case of unprovoked aggression justifying conquest, an uncivilized population has rights which make its free consent necessary to the establishment over it of a government possessing international validity.”Footnote ⁷² Accordingly, military operations were typically referred to as punitive expeditions, implying retaliation for the violation of the rights of Western powers such as those agreed upon in a protectorate agreement. The Sack of Benin of 1897, for example, was explained as a retaliation for the violation of bilateral trade agreements and the killing of members of a British mission to Benin. Whatever the historical assessment of those incidents ultimately might be,Footnote ⁷³ the submission of the entire Kingdom of Benin can hardly be considered a proportionate retaliatory response.

In summary, given the unbroken tradition of a discourse of legitimacy, it is sound to argue that the bellum iustum doctrine was considered to be the predominate doctrine, which, at the same time, puts the relevance of liberum ius ad bellum into perspective. Acknowledging the necessity of a just cause for war fundamentally alters the legal assessment of any conquest and occupation. Regarding spoliation in particular, it is often overlookedFootnote ⁷⁴ that the doctrine of just war precludes the unlawful occupier from acquiring private and public cultural property. This specifically excludes legitimations based on military necessity and compensation for war expenses. Hence, the spoliation and confiscation of both private and public cultural property during the period of colonialization of sub-Saharan states requires historically sound justification. In general, it seems unlikely that such a justification can be provided.

Validity of protectorate and cession treaties in colonial contexts

Western powers also tried to acquire territory and sovereignty by means of cession of territory. To name some British examples, this was the case with the Lagos Treaty of 1861,Footnote ⁷⁵ the treaty with the King of Bagroo and his chiefs of the same year, and the treaty regarding the territory of Badagry.Footnote ⁷⁶ The French concluded various cession treaties with African rulers starting from the beginning of the nineteenth century.Footnote ⁷⁷ The violent colonial context necessitates the historical analysis of each agreement and the intricate discussion of the requirements of valid international treaties in the nineteenth century. According to Lindley, the validity of international agreements requires the absence of fraud or coercion.Footnote ⁷⁸ However, this intuitive rationale is challenged in the context of peace negotiations. In addition, the agreements must have been comprehensible to the local representatives in terms of language and the legal concepts used.Footnote ⁷⁹ The support for these requirements was not necessarily motivated by a desire to protect Africans, but, rather, to create a title that the Western powers could recognize as valid among each other. However, as a consequence, colonial agreements still required free and informed consent from the perspective of legal doctrine.Footnote ⁸⁰ Van der Linden additionally points out that some protectorate treaties were kept vague in order to give Western powers a margin of discretion in the “twilight zone between cession and protectorate,”Footnote ⁸¹ which again introduced challenges to interpretation.Footnote ⁸²

The most problematic treaties are undoubtedly those imposed on African societies through threats of force. In theory, peace treaties served the goal of ending the cause of warFootnote ⁸³ – typically the alleged aggression by the enemy. The peace treaty would then arrange for compensation for the costs of war. Hence, the validity of peace treaties was based on the just war doctrine.Footnote ⁸⁴ Vattel provides a corresponding passage in his writings: “[The aggressor] must restore what he has unjustly taken, must reimburse the expenses of the war, and repair the damages.”Footnote ⁸⁵ However, taking practical consideration into account, he also argues that the pact sunt servanda principle prevails over fairness.Footnote ⁸⁶ Only “forced submission to conditions which are equally offensive to justice and all the duties of humanity” cannot be tolerated.Footnote ⁸⁷ Grotius follows the same line of thought, arguing that peace treaties serve to end the cause of war and provide for compensation.Footnote ⁸⁸ At the same time, they are binding even if concluded under coercion. However, the validity of unequal treaties always remains undetermined to some degree: “It does not follow that the party who has extorted some such promise by an unlawful war can retain what he has received without violating the honor and duty of a good man, or even can compel the other to hold to the agreement, whether sworn or not. For, essentially and in its nature, the transaction remains unjust.”Footnote ⁸⁹ Whilst both scholars emphasize the imperative to achieve peace even by tolerating unequal peace agreements, they still provide a pathway for (later) revocation based on unfairness. Despite repeated invocation of pacta sunt servanda, revisions remained thinkable.Footnote ⁹⁰ This was certainly the case where the cession of territory threatened the existence of a state.

Specifically, in the context of spoliation and translocation of cultural property, the doubts regarding the validity of unequal treaties resurface. The inclusion of cultural property in peace agreements in the nineteenth century reveals that the dispossession of cultural property already required justification. Acquisition by mere occupation was already rejected at the time.Footnote ⁹¹ For example, the Armistices of Bologna and the later Treaty of Tolentino signed in 1796 and 1797 between the Papal States and the French Republic, foresaw the transfer of more than one hundred paintings and other works of art to the French.Footnote ⁹² Relevant parts of the European public and even French military personnel still opposed the confiscations.Footnote ⁹³ In the context of colonial treaties, both the lack of legitimate cause for war and coercion were often present. Vattel specifically refers to treaties concluded between Cortés and the Empire of Mexico, arguing that all subversive countermeasures by the Mexicans would have been legitimate.Footnote ⁹⁴ Regarding cultural property specifically, the Congress of Vienna and the subsequent restitutions provide the blueprint to understand the inner workings of unequal peace treaties. The peace treaties with the French were initially tolerated to achieve peace. However, the transfers were still considered illegitimate,Footnote ⁹⁵ and their restitution did not require a new legal basis (actus contrarius).Footnote ⁹⁶ In particular, restitution clauses were not deemed a necessity.Footnote ⁹⁷ A main negotiator at the Congress of Vienna, Lord Viscount Castlereagh, argued that the spoliation had been “contrary to every principle of justice and the usages of modern warfare” and that the concluded armistices did not provide a valid title for the acquisition of spoils.Footnote ⁹⁸ These same principles apply to colonial conquest. The analysis will typically lead to the conclusion that the agreement concluded during an unjustified occupation under duress is invalid.

The origins of the prohibition of spoliation

Having explored the relevance of the just war doctrine for the assessment of colonial conquest and unequal treaties, I will shortly turn to the already well-studied development of the prohibition of spoliation. Throughout ancient and medieval times, conquest and taking spoils to compensate for war expenses were considered lawful.Footnote ⁹⁹ Grotius, for example, argued in favor of acquisition by occupation.Footnote ¹⁰⁰ However, while he held that enemy property was not protected under Roman or modern international law,Footnote ¹⁰¹ he pleaded for moderation based on moral grounds.Footnote ¹⁰² It should also be noted that he repeatedly contextualizes claims for compensation with just causes for war,Footnote ¹⁰³ which completes the contradiction. How could the aggressor legally acquire spoils in an unlawful war? Vattel then draws the consequence from this, declaring that cultural property may only be seized to weaken the enemy’s military efforts or for punishment in just wars.Footnote ¹⁰⁴ He unambiguously connects compensation by spoliation to just causes of war.

Much later, the Congress of Vienna (see above) implicitly adopted this rationale, representing the first distinct historical moment where the practice of unjustified spoliation was rejected as a means of acquisition during unjust wars.Footnote ¹⁰⁵ Accordingly, Jenschke Footnote ¹⁰⁶ and Sandholz Footnote ¹⁰⁷ argue that the norm was established in the aftermath of the Napoleonic campaigns and at the Congress of Vienna.Footnote ¹⁰⁸ In addition to the repatriation of their cultural property, the Papal State and Austria,Footnote ¹⁰⁹ as well as Egypt under Ottoman rule,Footnote ¹¹⁰ passed laws restricting the export of cultural goods, which further supports the argument. However, contemporary scholars in part reference older state practices when trying to determine the adoption of the prohibition as a binding norm.Footnote ¹¹¹ They date it to the mid-eighteenth centuryFootnote ¹¹² or the beginning of the nineteenth century.Footnote ¹¹³ This article does not go into the details of this discussion, it simply supports the majority opinion that the ban was at least introduced with the Congress of Vienna, which is sufficient for the argument regarding the period of colonization of sub-Saharan Africa.

The prohibition of spoliation in the second half of the nineteenth century

A legal text often cited as the central source regarding the protection of cultural property during the second half of the nineteenth century is the Lieber Code of 1863.Footnote ¹¹⁴ Its articles, 31, 34, and 36, mainly provide that “ownership is to be settled by the ensuing treaty of peace,” mirroring the primary peacekeeping function of peace treaties discussed above. Aligned with national provisions on lawful conduct during the seizure of property,Footnote ¹¹⁵ the Code further provides that “in no case shall [such works] be sold or given away […] nor shall they ever be privately appropriated, or wantonly destroyed or injured.” The provisions reflect traditional concepts regarding the seizure and acquisition of cultural property by means of negotiation. Hence, the Lieber Code did not introduce an all-encompassing prohibition of spoliation of cultural property, it referred to peace treaties. It is also silent in regard to protecting existing private property positions in peace negotiations.

Scholars at the time, instead, emphasized the significance of safeguarding private and cultural property during times of war.Footnote ¹¹⁶ Bluntschli explains the underlying rationale for the protection of private property: “Since the war is not being waged against civilians, there is no reason in the law that private law should perish or be subjected to the whim of the enemy.”Footnote ¹¹⁷ Given its peaceful cultural purpose, cultural property cannot be seized.Footnote ¹¹⁸ However, he also considers private cultural property to be the subject of peace treaties.Footnote ¹¹⁹ Like his predecessors, he emphasizes the principle of pacta sunt servanda in the context of peace treaties,Footnote ¹²⁰ but makes an exception where the existence and development of the conquered state are at stake.Footnote ¹²¹ The argument regarding the development of the state is potentially linked to the much later reference to the doctrine of self-determination in the twentieth century.Footnote ¹²² Bluntschli’s contemporary Fiore held a similar view, arguing that cultural property cannot be seized,Footnote ¹²³ and that coerced contracts are invalid where physical violence is involved.Footnote ¹²⁴ Just as with Grotius and Vattel, the tension between banning spoliation and unequal peace treaties is tolerated by these later authors, given the greater political goal to end violent conflicts. However, the fundamental legal principles of just cause and free consent cannot be set aside completely. Bluntschli was, therefore, forced to uphold the just war doctrine whilst dissociating it from the practical consequences of war and unequal treaties.Footnote ¹²⁵

Leaving the question of unequal treaties unanswered, the Brussels International Declaration concerning the Laws and Customs of War of 1874 Footnote ¹²⁶ at least clarified the questions of spoliation during an ongoing war. What we discover is an idiosyncratic convergence of the protection of private and cultural property. The Brussels Declaration provides that “[…] Private property cannot be confiscated” (Art. 38), and that “the property of municipalities, that of institutions dedicated to religion, charity, and education, the arts and sciences even when State property, shall be treated as private property” (Art. 8). The declaration differentiates between state property usable for military purposes (Art. 53) and public property designated for cultural activities, civil functions, or religious practices that fall under the protective framework of private property and, therefore, cannot be seized (Art. 56). This understanding extends the rationale that wars are not waged against civilians and their private property, extending it to public goods that serve civilian use remaining consistent with the civilian-combatant dichotomy.Footnote ¹²⁷ Hence, cultural property is not only protected by (international) public law but also under national private law, holding significance for the causes of action for restitution (e.g. replevin or the rei vindicatio). These provisions and the underlying concept were later incorporated, identically, in the Hague Conventions of 1899 and 1907 (Arts. 46 and 56). The seamless continuation indicates that the ban on the spoilation of private and public cultural property was perceived as a firmly established norm. Since international conventions were often regarded as the formal recognition of already established customary norms,Footnote ¹²⁸ it is perfectly reasonable that the Brussels provisions only codified already binding customary norms.

In summary, looking at state practice we find restitutions taking place in parallel to a discourse of legitimacy, reaffirming just cause as the fundamental requirement for war, spoliation, and compensation.Footnote ¹²⁹ Positivists later stressed the necessity of conventions,Footnote ¹³⁰ a requirement met through the incorporation of the ban on spoliation in the Brussels Declaration of 1874 and the later Hague Conventions of 1899 and 1907. Hence, the norms safeguarding cultural and private property were established prior to the Berlin Conference of 1884-85,Footnote ¹³¹ which marked the onset of the most aggressive phase of colonial conquest of the nineteenth century. Scholarly doctrine and conventions seem to undermine these principles by tolerating the transfer of cultural property based on unequal peace treaties. However, they also provide exceptions for cases of straightforward violent coercion, or where the existence and development of a state are under threat. Concerning colonial cessions, protectorate treaties, and resulting transfers of cultural property, their validity should, therefore, be evaluated case-by-case to establish whether requirements for consent were fulfilled or whether exceptions apply.

Universality and non-retroactivity

After the examination of the temporal scope of the prohibition of spoliation, I will now turn to the pivotal and overarching question, asking whether African societies were subject to international law and the prohibition of spoliation. First, the article argues that due to the universal claims of natural law, international law had at least a self-binding effect on Western states, including their interactions with non-Western states. Second, the article argues that the prohibition of spoliation specifically represents an expression of universal natural law principles; in particular, those of state sovereignty and the right to property. The prohibition was introduced during a period that directly relied on natural law as the central source of international law.Footnote ¹³² By limiting the universal principles of state sovereignty, private property, and, subsequently, the protection of cultural property to Western states, scholars and statesmen in the nineteenth century disregarded the universal and, therefore, nondiscriminatory structure of natural law. Natural law principles could not simply be abrogated to the detriment of third parties by agreements inter partes or later positivist demands. This even aligns with the central goal of TWAIL to achieve “a more just international legal order.”Footnote ¹³³ However, we should not reject Western international law, but rediscover and insist on the nondiscriminatory character of its natural law concepts. It is crucial to address fears that such an endeavor contradicts the principle of non-retroactivity.Footnote ¹³⁴ However, it seems clear that we cannot equate the interpretation of nineteenth-century law from the perspective of natural law principles with the retroactive application of today’s laws. The reference to universal principles of natural law does not obscure the history of international law but outlines its conceptual foundations.

International law as a universal framework

Whether based on the notion of an international community (civitas maximas) or the self-interest of states, natural law provides universal rights and obligations equally applicable to all states erga omnes. Regarding the topic of sovereignty, the standard for civilization has already been uncovered as a universal ethical concept (see above). Vattel describes natural law in this universal and equal manner: “Since men are naturally equal […] nations composed of men […] are naturally equal, and inherit from nature the same obligations and rights.”Footnote ¹³⁵ In addition to this universal nature, natural law principles were in part also thought to be binding jus cogens vis-à-vis conventions and customs. Vattel states that “every nation is bound to relinquish [an unjust or unlawful custom] since nothing can oblige or authorize her to violate the law of nature.”Footnote ¹³⁶ This concept of universal jus cogens was later upheld by many scholars in the nineteenth century.Footnote ¹³⁷ Halleck writes in 1874: “Customs […] which are unjust and illegal, and in violation of natural and divine law, have no binding force.”Footnote ¹³⁸ The same accounts for Bluntschli, who held that treaties contradicting recognized human rights or jus cogens are void.Footnote ¹³⁹ This specifically applies in times of war, as noted by Lorimer in Reference Lorimer1884: “The rights of civilisation, as jura universalia, impose corresponding duties, officia or debita universalia, which limit not only the means which belligerents may jurally employ, but the manner in which they may employ them.”Footnote ¹⁴⁰ Nineteenth-century international lawyers took the universal application of fundamental ethical principles for granted. However, they failed to recognize the consequences of this concept in the context of colonialism. They simply ignored arising contradictions; in particular, when they held African states and communities accountable for alleged violations of universal ethical and legal principles – particularly the practice of slavery – while denying them equal enjoyment of universal rights.Footnote ¹⁴¹ It should also be noted that universality and non-discrimination are relevant in the context of the persistent objector rule, which could be brought up as a defense for the Western states in this context. While the objection to a custom by a state – in our case the prohibition on spoliation – is tolerated, it cannot be effective against individual states. Furthermore, if the prohibition is, instead, considered to be a peremptory norm (jus cogens) – as is the case todayFootnote ¹⁴² – the consistent objector argument would not be available in the first place.

Private Property as a universal right

Modern private property theory finds its fundamentals in universal natural law reasoning. First, from the perspective of international law, the protection of property is mediated through the state. Accordingly, foreign acts related to property in the state are ineffective. This also follows from the notion of state sovereignty. During times of war and when spoliation occurs, however, the protection of property as a mere derivative of the state’s sovereignty seems insufficient. In my view, it is also the underlying understanding of the Brussels Declaration and the Hague Conventions – which determine that public cultural property follows private property protection – and that the prohibition of spoliation finds its ultimate foundation not in a state’s sovereignty but in universal property rights. Early modern doctrine maintained that private property emerged from a state of nature before communities started to hold land and goods in common. This was also the understanding of both Grotius Footnote ¹⁴³ and Vattel. Footnote ¹⁴⁴ However, it was still debated whether property could be considered a natural right based on labor (natural right theory)Footnote ¹⁴⁵ or if it originated from the social contract of the community (contract theory).Footnote ¹⁴⁶ The latter concept suggests that the existence of property depends on a society’s sovereignty, meaning the attribution of land and goods by the state. In this debate, however, important scholars and sources supported the natural rights theory. This includes, for example, scholars like Blackstone: “[…] Every m[a]n [is] entitled to enjoy [property] whether out of society or in it.”Footnote ¹⁴⁷ and Art. 2 of the French Declaration of the Rights of Man and of the Citizen of 1789, which conceives property as a natural and imprescriptible right.Footnote ¹⁴⁸ Thiers reaffirmed the theory in Reference Thiers1848, stating that “property is a permanent fact, universal in all times and in all cultures.”Footnote ¹⁴⁹

However, I do not contend that the natural rights theory prevails over the contract theory. Instead, they potentially complement each other: During times of peace, the fate of property depends on its regulation by the state. At this stage, the international law dimension of private property remains mediated through the state’s sovereignty. Natural rights, however, come into the foreground where unjust expropriations or conflicts between states occur. This is particularly true whenever a society collapses because of an internal conflict, war, or occupation. In such scenarios, individual rights require protection beyond mediation via sovereignty. As said, this rationale underlies the concepts formalized by the Brussels Declaration and the Hague Conventions. The important contribution of these documents was to emphasize the extension of protection to public cultural property used for civil purposes. Based on natural rights, the ban on spoliation offers protection irrespective of the recognition of the host state’s sovereignty. From this follows for the colonial context, that both the private property of Africans and their public cultural property should have been recognized as such, even when the sovereignty of their state was rejected!

African customary property and possessory rights

Precolonial African states and communities had established complex legal rules regarding individual, tribal, and familial property. Our knowledge of the historical details, however, remains somewhat limited given the oral tradition.Footnote ¹⁵² These legal positions were sometimes characterized by Western scholars as mere relative obligations between chiefs, communities, families, and individual members in the context of status relationships.Footnote ¹⁵³ However, we now understand that they were instead conceived as communal or familial propertyFootnote ¹⁵⁴ administered by an elder leader.Footnote ¹⁵⁵ Individual rights were often designed as possessory rights, which were not freely tradeable.Footnote ¹⁵⁶ However, the systems always allowed determining the possessor of a specific right in the land (usus fructus, administration rights)Footnote ¹⁵⁷ or a movable.Footnote ^{158 ,} Footnote ¹⁵⁹ The right to use land could also be subject to sale or mortgage if the members of the community were involved.Footnote ¹⁶⁰ Ultimately, control lay with the community and not with the individual when it came to valuable goods. This solution mirrors European concepts of public property, property held in trust, the medieval dominium of a guild or a house,Footnote ¹⁶¹ and, specifically, cultural property understood as an inalienable heritage.Footnote ¹⁶² Western Scholars recognize art collections as aggregated assets, arguing for the restitution of individual pieces to restore their integrity.Footnote ¹⁶³ Moreover, non-individualistic forms of property were rarely subject to abolition in the West, a prominent exception being the Fideicommissum,Footnote ¹⁶⁴ which, in turn, shows that even in modern times, forms of common property or possession are by no means alien to Western law. In summary, collective forms of property were recognized in domestic Western settings and the same recognition should have been afforded to African customary rights. To simply assume that there were no sufficient rules and rights regarding land and property seems discriminatory per se. Instead, the modification of the well-known Roman law principle to “ubi societas, ibi proprietas” appears more intuitive.

The relation of African customary law to colonial treaties and regulation

Colonial treaties often acknowledged the property rights of local inhabitants, which aligned with the principle in international law that mere cession of territory did not affect land ownership.Footnote ¹⁶⁵ For example, while the German-Cameron agreement foresaw complete cession of territory and sovereignty, it guaranteed the continuation of land rights: “The land now cultivated by us and the land on which cities are built shall remain the property of the present owners and their legal successors.”Footnote ¹⁶⁶ When read in context, the same is inferred by the Lagos Treaty of 1861 regarding the cession of Lagos Island to Britain: “[…] in the transfer of lands, the stamp of [the souverain] affixed to the document will be proof that there are no other native claims upon it […].”Footnote ¹⁶⁷ Similar provisions can again be found in the treaty regarding the cession of the Badagry territory to Britain.Footnote ¹⁶⁸ The broad recognition of private positions within colonial treaties was then transposed into internal colonial regulations, but the latter did not typically override local law. The relationship was, rather, one of continuity and subsidiarity. Under English law, only local laws that conflicted with Western moral standards were considered invalid, which, for example, included laws concerning slavery. In this regard, a Privy Council decision from 1722 is commonly cited: “The laws and customs of the conquered country shall hold place unless where they are contrary to our religion, or enact anything that is malum in se or is silent, for in all such cases the laws of the conquering country shall prevail.”Footnote ¹⁶⁹ Blackstone also endorsed the continuity concept.Footnote ¹⁷⁰ It then persisted into the late nineteenth century and was followed by the Supreme Court Ordinance of 1876 regarding the Gold Coast Colony,Footnote ¹⁷¹ and in Nigeria and Ghana.Footnote ¹⁷² It is reasonable to assume – but is subject to further case study – that the customs on cultural and private property typically fulfilled the requirements.

Following the same logic of subsidiarity and continuity, German regulation left customary law to the local inhabitants.Footnote ¹⁷³ The contemporary scholar Gerstemeyer went further and asserted that customary laws also applied in private relations between local inhabitants and German citizens.Footnote ¹⁷⁴ As far as individual rights were concerned, the land ordinances in German East Africa required that customary law positions be taken into account and that agreements should be concluded with local communities.Footnote ¹⁷⁵ Anyone could acquire land ownership by providing proof that they had enclosed the land for two years. Similar arguments hold for German-occupied Cameroon,Footnote ¹⁷⁶ where the KronlandgesetzFootnote ¹⁷⁷ and the EnteignungsverordnungFootnote ¹⁷⁸ acknowledged customary rights. However, since the terra nullis doctrine was applied, land distribution was still often enforced violently, and legal uncertainties prevailed in practice.Footnote ¹⁷⁹ Decisive for the case of cultural property, however, was that movables were not regulated, which means that potentially discriminatory regulation in the context of ownership of landFootnote ¹⁸⁰ did not extend to movable cultural goods.Footnote ¹⁸¹ Following the continuation principle, local customary law applied to these goods.

Recognition of individual rights by scholarship

However, in some cases, treaties and internal regulations remained silent on the question of individuals’ rights.Footnote ¹⁸² Relevant answers must, therefore, be derived from the scholarly literature of the nineteenth century. Following the above-described natural law concepts and the Lockean notion of acquisition of property by labor, individuals could acquire rights over land by cultivation and movables by their production. Nuzzo has provided us with an overview of the scholarship on this question.Footnote ¹⁸³ Nineteenth-century scholar Fiore argued that land could not be occupied if it had already been cultivated by Africans.Footnote ¹⁸⁴ Catellanis stated that private rights persisted despite the right of the colonial powers to occupy empty territory.Footnote ¹⁸⁵ Even Bluntschli, who denied Africans their property rights, admitted that local inhabitants could not be displaced against their will.Footnote ¹⁸⁶ In general, the scholarship agreed that arbitrary occupation of cultivated land was generally unlawful. This strongly suggests that rights to movable property persisted – cultural property is typically the result of labor or the cultivation of a specific site.

Rejection of African claims by Western courts

However, Western courts often rejected property claims and justified spoliations or expropriations, creating not only tension with natural law principles but, as we have seen, also with colonial treaties, colonial regulation, and scholarly opinion.Footnote ¹⁸⁷ Whilst this is a topic of national law, some aspects should be noted here. In general, there appears to be a problematic link between the historical denial of African private property claims and some decisions by today’s courts. The infamous 1919 UK Privy Council decision in Re Southern Rhodesia exemplifies the discriminatory rationale: “It would be idle to impute to such people some shadow of the rights known to our law and then to transmute it into the substance of transferable rights of property as we know them.”Footnote ¹⁸⁸ Without relying on the underlying racist rationale, later decisions have sometimes rejected restitution claims based on private property.Footnote ¹⁸⁹ Typically, they argue that restitution is a question of diplomacy and public law only. However, in most systems, such court decisions can only affect the parties involved due to the subjective constraints of the res judicata doctrine.Footnote ¹⁹⁰ Hence, the decision may be limited to the specific case at hand without establishing a broader effect. In jurisdictions with binding precedents, however, such decisions can be overruled by arguing human rights violations under the per incuriam rule. Decisions such as in Re Southern Rhodesia clearly stood in contradiction to international legal principles, colonial treaties and regulations, and scholarship, which undermines their relevance within the system.Footnote ¹⁹¹