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Maastricht University

The Origins of the Idea of Military Occupation

Peter Stirk

In 1844 the eminent jurist August Wilhelm Heffter lamented the common failure to clearly distinguish between conquest and occupation. Approximately thirty years earlier he had witnessed both occupation and conquest from the perspective of his native Saxony in the final phase of the tumultuous events that put the idea and practice of occupation on the international agenda – the French Revolutionary and Napoleonic wars, including the Allied occupation of France that ended in 1818. In this article I suggest that a case can be made for treating some earlier events prior to 1792 as instances of military occupation, and some events between 1792 and 1818 from the perspective of either occupation or conquest. The language and practice of occupation and that of conquest were not hermetically sealed; the confusion is as much part of the story as the distinction.

Nevertheless, if conquest is understood as the acquisition of territory and the displacement of the existing ruler by a new sovereign, the idea of military occupation, understood as the control of territory and exercise of authority over the inhabitants by a power that is not the sovereign power, either by virtue of the force at its disposal or in accordance with some treaty or convention, was widespread in the years 1792 to 1818. During this period and in its aftermath, courts and learned jurists started providing a rudimentary clarification of the concept of occupation. Conceptual clarification followed rather than preceded what might loosely be called the practice of occupation.

If this is accepted, it raises two questions. First, why did the idea of military occupation not emerge earlier? Second, what happened in those tumultuous years that introduced the idea and practice of occupation?

Conquest and Occupation before 1792

Part of the answer to the first question – why did the idea of occupation not emerge earlier – lies in the claims to legitimate possession made by those who seized territory and exercised authority over citizens and the reactions of their opponents. Those claimants whose legitimacy was disputed were typically denounced as usurpers, traitors or simply enemies rather than as occupants. Argument  therefore turned on what sufficed to make a successful claim to legitimate power, rather than on the rights and obligations of an occupier that did not claim sovereignty over the territory.

Here it is useful to distinguish three distinct approaches to the subject. First, in the works of eminent jurists of the seventeenth and early eighteenth centuries, such as most notably Grotius, Pufendorf, and Bynkershoek, we find the most extreme forms of justification of conquest, drawing as they did on the practice and law of the ancient world. Even here, however, Christian sentiment or expedience could be invoked to recommend a milder policy, including leaving in place the institutions and religious practices of the conquered. That might sound like the injunction later imposed on occupants in the international law of occupation, but at the time it reflected rather the nature of the composite states in which vigorous assertion of sovereignty was quite compatible with diverse government of the distinct parts of the state.

The second approach is illustrated by the arguments that sovereigns or other rulers – for not all saw themselves as sovereigns – deployed to justify their claims. Here, while references to brute conquest can be found, such justification seems to have been generally regarded as dangerous. The articulation of just title, supported by factual possession and the endorsement of elements of the indigenous elites leading to cession by treaty, provided a much stronger set of arguments. The key element here is the claim to just title, readily found given the nature of the monarchical system predominant in Europe at the time. At this level the system was skewed towards the language of rights of legitimate authority, not the language of power and  authority characteristic of occupation..

The third approach depended on the relationship between the invading power or their agents and the population subject to them. Here, there seems to have been considerable diversity in the kinds of claims made. In some instances at least factual possession seems to have been taken to entail the immediate displacement of sovereignty. The most extensive study of this issue, however, by Irénée Lameire published in 1902, concluded that no general conclusion could be safely drawn as to whether possession of territory did or did not displace sovereignty. Interestingly, one factor that contributed to his hesitancy was that there were numerous political actors and structures who were simply not regarded as sovereigns or whose status as sovereigns was in doubt, especially in the context of the Holy Roman Empire.

It is not difficult to see how this could open the way for complex justifications of the invader’s authority and rule, rather than the precarious assertion inherent in the concept of occupation, of authority without sovereignty. Taken together, these three approaches used to justify rule over conquered territory in pre-Revolutionary Europe suggest that while some instances displayed features that we would now consider typical of occupation, such as the maintenance of existing institutions and practices or the devolution of power to local elites, the broader scholarly and political discourse of the period was not conducive to the emergence of the language and idea of military occupation.

The Idea and Practice of Occupation during the Revolutionary and Napoleonic Wars

In answer to the second question – what happened during the revolutionary and Napoleonic wars to introduce the idea and practice of occupation – it is useful to emphasize that the idea of occupation crystalized because of several factors. The principled renunciation of conquest in Title VI of the French Constitution of 1791 was a significant development, but this should not serve to occlude that the French Revolutionaries were capable of conjuring up justifications of conquest quite as radical in their way as any put forward by Grotius. More important were instructions issued to generals and the various civilian agents of the Republic, especially as they turned from ideas of liberation to the practice of managing and exploiting territory they had seized, but not yet decided what they wanted to do with it. The instructions authorized by the Committee of Public Safety in September 1794, for example, ran to 31 articles focused on the exercise of provisional authority, although they referred to ‘conquered’ territory throughout. In that sense, the practice of occupation could be said to have preceded the idea.

A second set of factors was the provisionality of the entire Revolutionary and Napoleonic order of Europe. It is not necessary here to subscribe to the desire of the ultimate victors to delegitimize the Revolutionary and Napoleonic structures. It is sufficient simply to record the references to provisional authority used by Napoleon and his collaborators. There could be no definitive settlement until peace was achieved, and peace was achieved only by the defeat of Napoleon.

A third set of factors was the numerous treaties and conventions between the Republic, and later Napoleon, and defeated and allied powers, including the sister republics. Sometimes these agreements used the word occupy and sometimes they did not, but they all provided for the presence of French troops and sought to regulate the tension between the authority of the indigenous powers and that of French forces. They frequently provided for the exercise of restraint by French forces and almost as frequently were followed by violation of the promised restraint. Nevertheless, these documents provided often detailed specification of how their authors thought the occupation ought to be conducted.

A fourth set of factors was the proclamations issued by Revolutionary and Napoleonic generals, especially where it was unclear what the ultimate fate of the territory or town was to be. Sometimes the assertion of ‘possession’ could look very much like the assertion of conquest and the immediate displacement of sovereignty and could induce vigorous protest and demands that the status of the town be couched in other terms, including that of occupation; but this was not always so. Whatever the response, these proclamations entailed some formal specification of the relationship between the invader and the inhabitants. Generals conscious of their slight administrative resources had an interest in exhibiting some moderation.

A fifth set of factors concerned the satellite kingdoms nominally ruled by Napoleon’s military commanders and relatives. Here despite familial ties and common nationality, for Napoleon insisted that they remained French despite being rulers of non-French states, Napoleon became dissatisfied with the conduct of Joachim Murat in Naples and Joseph Bonaparte in Spain and ordered his generals to assert independent authority; effectively as if in occupation of the respective countries.

A sixth set of factors relates to the Allied, rather than the French revolutionary and Napoleonic occupations of German and French territory. (The Allied occupation of France from 1815-1818 will be discussed in the fourth and fifth articles in this series by Beatrice de Graaf and Christine Haynes). These were especially important because they were multilateral in nature and based upon the assumption that there was to be no assertion of conquest by the separate Allied states. Both the Central Administration headed by Baron von Stein, which was established in the wake of the battle of Leipzig and the Allied Administrative Council and related bodies were complex structures in which ideas of provisional administration were articulated in explicit contrast to practices of conquest.

Finally, there were those rudimentary conceptual distinctions drawn by the courts, especially by the French Cour de cassation as it sought to work out the legal consequences of the practice of occupation; a task that was made more difficult by the complexity and provisionality of Napoleonic Europe.

Two qualifications are necessary. First, the language of conquest was not displaced by the language of occupation. The two languages and associated practices jostled alongside each other, overlapping and often inducing as much confusion as clarification. Second, attempting to identify the relative weight of the different factors or to see them as fusing into some common understanding of military occupation at this time is probably unhelpful. It may be better to accept that their significance simply varied depending upon the circumstances of the people affected by them.



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Haynes, Christine, Our Friends the Enemy. The Occupation of France after Napoleon (Cambridge, MA: Harvard University Press, 2018).

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Graaf, Beatrice de, Fighting Terror after Napoleon (Cambridge: Cambridge University Press, 2020).

Kielmansegg, Peter Graf von, Stein und die Zentralverwaltung 1813/14 (Stuttgart: Kohlhammer, 1964).

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McCluskey, Phil, Absolute Monarchy on the Frontiers: Louis XIV and Military Occupation of Lorraine and Savoy (Manchester: Manchester University Press, 2016).

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Stirk, Peter M. R., The concept of military occupation in the era of the French Revolutionary and Napoleonic wars’, Comparative Legal History, Vol. 3 (2015), 60-84.

Stirk, Peter M. R., A History of Military Occupation from 1792 to 1914 (Edinburgh, Edinburgh University Press, 2016).


Picture credits:

Cover picture: Francisco Goya, El tres de mayo de 1808 en Madrid

Source: Wikipedia Commons

Peter Stirk has now retired. He was formerly Senior Lecturer in Government and International Affairs at Durham University, UK