Who Holds It Justly?

The concept of good faith (Treu und Glauben) has long served as a cornerstone of both German private law and international legal doctrine. Enshrined in Article 242 of the German Civil Code (BGB), it requires that contracting parties act honestly, loyally, and with due regard for one another’s legitimate interests. In international law, good faith likewise functions as a general principle governing treaty interpretation and performance of treaties. Yet where agreements are concluded between unequal parties, for instance, between a declining empire and an ascendant colonial or industrial power, the meaning of good faith becomes deeply problematic. Can such a contract genuinely be said to reflect consent when one party’s sovereignty is fragile or structurally constrained?

This tension lies at the heart of disputes over cultural property, exemplified by the case of the Pergamon Altar, removed from Ottoman territory in the late nineteenth century and now exhibited in Berlin’s Pergamon Museum. The agreements concluded between the Ottoman Empire and the German Empire in 1878–79 concerning the Pergamon finds were negotiated at a time of pronounced Ottoman political weakness and financial dependency. Although these arrangements were formally lawful, they can scarcely be regarded as products of genuine consent or good faith. The Ottoman government, struggling against political fragmentation and deepening indebtedness to European powers, found itself negotiating under palpable pressure. From a legal-philosophical standpoint, consent obtained under conditions of duress, structural necessity, or subordination cannot embody genuine good faith. This argument could be supported by Article 52 of the Vienna Convention on Law of Treaties. While the Convention addresses the most evident form of coercion, Article 52 highlights that a treaty is void when a State’s consent has been taken by the threat or use of force. The fundamental principle that consent taken by coercive conditions lacks validity is nevertheless instructive. The Pergamon arrangements, though not concluded under military threat, show structural and economic pressures that align with this broader conceptual concern. Even if one assumes that the transfer of the Pergamon finds were deemed to comply with the formal requirements of the 1906 Asar-ı Atika Nizamnamesi (the Ottoman Antiquities Regulation on archaeological excavations and the allocation of finds), its substantive content would still disclose elements of coercion and unjust enrichment. In this sense, the Pergamon arrangements anticipate what international law would later conceptualise as “unequal treaties,” concluded under circumstances incompatible with sovereign equality.

Within German law, Article 242 BGB positions Treu und Glauben as a corrective principle, preventing the enforcement of rights that have been obtained or exercised in a manner tainted by dishonesty, abuse, or breach of loyalty. The provision recognises that mere formal legality does not confer legitimacy where fairness has been violated. Transposed to the international context of cultural heritage, the Pergamon arrangements would not withstand such a standard: exploiting a weaker sovereign to acquire its antiquities is fundamentally incompatible with the equitable spirit that the requirement of good faith is intended to safeguard. Moreover, the ICOM Code of Ethics for Museums (2016) expressly calls upon institutions to take into account not only their legal title, but also their wider moral responsibilities when acquiring and retaining objects. In both legal and ethical terms, the continued possession of artefacts removed under such conditions demands critical re-evaluation.

The evolution of German law itself mirrors this moral awakening. The 2016 Kulturgutschutzgesetz (KGSG) marks a significant turning point in the regulation of cultural property, introducing comprehensive rules on the import, export, registration, and restitution of cultural objects. The statute embodies a conceptual shift: it reconceptualises good faith not as a presumption in favour of the possessor, but as a duty of due diligence owed to the broader cultural community.

Key provisions of the KGSG, such as Article 28’s import ban on cultural property unlawfully removed from its state of origin, Article 32’s definition of unlawful import, and the restitution procedures set out in Articles 49–53, significantly strengthen the position of source states such as Turkey. Section 72 further provides that the ownership of returned cultural property is determined by the law of the state of origin, thereby recognising the enduring title of the source state. Taken together, these provisions suggest that, at least within this framework, the protection of national cultural heritage has begun to outweigh the good-faith expectations of private possessors.

Nevertheless, certain provisions appear to constrain restitution. The temporal limitation in Article 52, the limitation period in Article 55, the compensation rights for bona fide acquirers under Articles 66–67, and the immunity from seizure laid down in Articles 73–76 all seem, at first glance, to favour existing holders such as museums. Yet such technical limitations cannot efface the moral and legal principles underlying international justice. Under doctrines such as ex injuria ius non oritur and Treu und Glauben, no right can arise from an act tainted by inequality or coercion. The compensation rights provided in Articles 66–67 presuppose genuine good faith, something that can scarcely be attributed to transactions concluded with a politically dependent Ottoman state.

This transformation also signals a redefinition of good faith itself. In modern legal and ethical theory, good faith encompasses moral responsibility and active inquiry in addition to formal consent. It requires due diligence in verifying provenance, transparency in documentation, and respect for the cultural and spiritual significance of objects. A museum cannot invoke good faith solely on the basis of historical purchase or formal legality. The Pergamon Museum’s reliance on a nineteenth-century contract concluded under highly questionable circumstances cannot withstand this modern standard. Nor can the argument that artefacts were “safer in Europe” continue to serve as a justification. Contemporary Turkish institutions are fully capable of ensuring preservation, and genuine preservation today entails restoring context as well as form.

From a public international law perspective, good faith operates as a general principle governing state conduct and interacts closely with the doctrines of state responsibility and restitution. Although the Pergamon case predates the principal international conventions on cultural property, the fundamental principle ex injuria ius non oritur, that no right can arise from a wrongful act, remains applicable. Domestic legality cannot excuse conduct that is contrary to evolving international norms. By analogy, the continued possession of artefacts acquired through exploitation or political dependence cannot be legitimated solely by reference to historical legality.

Ultimately, the transformation of German law under the KGSG reflects a broader international shift from formal legality to substantive justice. The Pergamon Altar, admired for its universal artistic value yet estranged from the cultural soil that gave it meaning, embodies this moral paradox. Good faith, once invoked as a shield by possessors, has been redefined as a standard of responsibility toward source communities. Agreements concluded under unequal conditions, such as the Ottoman–German exchanges, cannot meet this standard. Legal ownership must therefore coexist with ethical stewardship. The decisive question is no longer simply who holds title, but who holds it justly. In this light, Germany’s modern legal order, through the KGSG and its incorporation of international norms, marks a significant step toward recognising that justice in cultural heritage cannot rest on the law of possession alone, but must ultimately rest on the law of conscience.