3.4.2 Peace and Conflict in Modern History (ca. 1800–1900)

Beatrice de Graaf, Nere Basabe, Jan Hansen

© 2023 de Graaf, Basabe, and Hansen, CC BY-NC 4.0 https://doi.org/10.11647/OBP.0323.35


There is a lingering debate among historians as to whether the long nineteenth century—the period between 1789 and 1918—should be considered an age of relative peace with localised and short-lived wars, or whether it should rather be seen as a particularly violent century. First, the period saw the Napoleonic Wars, which came to an end in 1815 and which had devastating consequences for the whole of Europe. Additional wars throughout the century included a series of regional conflicts, and—at the very end—the beginning of the First World War. But the era also witnessed the development of collaborative institutions and the idea of the ‘Concert of Europe’, which helped to contain violent conflicts. The nineteenth century also gave birth to increasing transnational peace movements. Certainly, the answer to the question of whether the nineteenth century was particularly violent or particularly peaceful depends on where one looks. In their colonial empires, the European powers were anything but peaceful. There, they exercised brutal violence against indigenous populations and deprived the colonised territories of their resources. The European powers were also indirectly involved in the American Civil War (1861–1865), which was extremely costly. The nineteenth century saw both the birth of industrial warfare, and has nonetheless often been characterised as an epoch of ‘peace and prosperity’. How can we explain these two phenomena and their apparent contradiction?

The Birth of Industrial Warfare

With the revolutionary and Napoleonic Wars between the years 1792–1815, an age of continuous warfare reached its nadir. Although the battles of 1792–1815 had not been bloodier or more gruesome than the battles during the Seven Years’ War (1756–1763), historian David Bell nonetheless speaks of a new, ‘total war’. Civilian casualties range between 0.75 and 3 million; in Tirol, Spain, Italy, Russia, and France irregular bands of armed rebels and citizens fought alongside conscripted soldiers. On top of all casualties, countless soldiers came home as invalids, thereby adding to the misery and poverty of their family members. In the Netherlands, seventy percent of conscripts never returned.

These wars were among the last belonging to the ‘age of men’, when wars were waged with infantry and cavalry. The ‘age of machines and technology’, with its industrial capacities to destroy, had not yet arrived, but the last large battle of the Napoleonic Wars, the Battle of Waterloo (1815), already demonstrated the tremendous power of artillery, devastating columns of infantrymen. The socio-economic, military and especially human costs of these wars were catastrophic. They provoked new reflection from figures such as the Prussian strategist Carl von Clausewitz, who himself participated in the wars, developing his military theory in the book On War (published posthumously in 1832). More than half of all the casualties and victims fell in the last three years of the wars, when the scale of armies and battlefields grew considerably.

The effect of this was first and foremost to create vivid, lasting memories of death and destruction in the minds of the citizens of Europe, which endured after the war was over in 1815. The wars left not just the European continent, but also India, the Middle East (with the sack of Jaffa by Napoleon in 1799), and the Americas with deep traumas and scars of a protracted period of warfare. A striking example of these traumas (and their long aftermath) is the massacre of the French and French Creole population in the wake of the Haitian Revolution in 1791. The ensuing battles and massacres occurred in the context of France’s long and troubling colonial rule in Saint-Domingue (as Haiti was called before 1804), but it was also a ‘subaltern genocide’ against the colonisers, killing between 3,000 and 5,000 people and demonstrating how new technologies of warfare were already being used in non-European spaces by1804.

The wars also prompted a transition away from increasingly obsolete fortresses—with the last great fortresses being erected along the north-eastern border of France, the ‘Wellington Barrier’, and along the North American East Coast. Instead, there was new investment in rapid transportation infrastructures (with the advent of railroads), new information and communication technologies, and the training and use of mass-conscripted armies. Napoleon had raised the stakes with his use of levées en masse and the introduction of semaphores (optic telegraphs) into his operational communications: the post-1815 monarchies and empires would not forget these developments.

The industrial age expanded the scope of warfare, both on land and at sea. Warfare moved from hand-to-hand combat and beyond the immediate visual range to an early form of remote warfare, ‘beyond the hill’. Because of technological improvements in rifles, firepower, explosive shells, guns, and accompanying infrastructures (thanks to innovations in metallurgy), warfare was carried out increasingly in trenches, with the Crimean War (1853–1856) as the first large-scale manifestation of this development. In the lead-up to the First World War, machine guns, chemical weapons, landmines, and early armoured tanks were already being tested and introduced. Many of these new techniques were tested in colonial territories and at sea, leaving Europe and the Americas more or less peaceful until the Franco-Prussian War (1870–1871), and the American Civil War. This high-casualty war between the US North and South is generally considered to be the first industrially fought war in modern history.

Peace and Prosperity?

The theory of ‘the long peace’ was compounded by Paul Schroeder in his seminal work The Transformation of Europe. Schroeder traced the intricate diplomatic settlement in and beyond Europe from 1763 to 1848, with a pivot on the Congress of Vienna and the ensuing Concert of Europe in 1815. According to Schroeder, the trauma and devastations of the previous years had prompted the powers of Europe to invent and consolidate mechanisms of alliance building—not just in preparation for war, but also for maintaining peace. The European powers tried out new instruments of conflict management, which in many cases preferred peaceful conflict resolution to the violent assertion of interests. A new type of diplomacy, based on negotiation, cooperation and the establishment of norms and rules, was attempted, and ultimately coalesced under the title of ‘European Concert’ in 1814–1815.

It is important to note that this post-1815 system should not be considered an era of ‘restoration’ since there had been no “turning back of the clock.” Instead, “the spirit and essence, the fundamental principles and operation, of the international system [...] were anything but backward looking, were instead progressive, oriented in practical, non-Utopian ways to the future” (Schroeder). Indeed, part of the explanation for the long peace is the fact that the self-appointed and so-called ‘first rank powers’ (France, Russia, Austria, Prussia, and Britain) kept consulting each other in ambassadorial and ministerial conferences. With only a handful of congresses taking place between 1648 and 1815, the generations following 1815 organised conferences on almost every issue that plagued international relations: conferences on the Belgian Question, the Papal Question, conferences on sanitation, on Syria, on the postal system, on seaports, and on the organisation of quarantine stations across the borders of the European lands.

From the mid-nineteenth century onward, attempts can be identified to codify legal standards for international relations, including warfare. Arguably the most famous example is the Lieber Code of 1863, which explicated the law of war for land battles in the American Civil War. A year later (1864), the first Geneva Convention initiated the modern law of war. The Hague Peace Conferences (1899/1907) finally brought far-reaching agreements on warfare, constituting one of the first attempts by the international community to abolish war as an institution. Even before the Lieber Code, fifty-five nations agreed in 1856 to the Declaration of Paris, which governed maritime warfare. This international system was far more institutionalised than the states system of the ancien régime, with its loose wartime coalition and cabinet wars. It was supported by ‘middle men’, second-tier officials, who invested themselves in the new culture of security, peace, and prosperity. When the traumas of the Napoleonic Wars waned, this system still did not completely dissolve or unravel in 1822, nor in 1848, as some historians have contended, but transformed itself, and was constantly reconfigured as a system of conflict and security, of empire and revolution throughout the long nineteenth century. The various ministerial conferences, ambassadorial meetings, the making of international law, and the inter-imperial ‘rage for order’ initiated by the empires of Europe did not cease to exist, but in fact spread across the world and intensified in scope and impact up until the First World War and beyond, when European ambitions and emotions set the world in flames once again.

The European Concert sanctioned the right to interfere in order to maintain the security of the states system as a whole. As a consequence, there were various military interventions against revolutionary countries that were seen as a potential threat to the system, because civil conflict between supporters of absolutism and liberalism was far from being eradicated. Resultant clashes included the Austrian invasion of Italy in 1821, and the French invasion of Spain in 1823. The Holy Alliance did not officially intervene in the Greek War of Independence (1821–1830) against the Ottoman Empire, but that lack of action itself triggered a massive mobilisation of public opinion and resulted in many volunteers across the continent mobilising to fight for the independence of Greece.

This transition not only occurred at the level of statesmen, diplomats, and generals, but also at the intellectual and societal levels. Liberal doctrine promised, in its most idealistic version, a future of perpetual peace, with warlike societies replaced by commercial societies: against a model of enemies and confrontation, the prosperity linked to free trade promoted peaceful exchange for the benefit of all. The nineteenth century thus saw the proliferation of a multitude of publications concerning peace and the emergence of organised pacifism and mass peace movements, all of which indicated a change in social values and norms.

These moments of conflict appear closely linked to the proliferation of schemes for ‘perpetual peace’, with the publication of such visions peaking at turbulent moments such as 1800, 1814–1815, or 1830. In Italy, between 1795 and 1800, at least 140 peace projects were proposed. The irenic ideal of perpetual peace was a long-standing medieval tradition. Most of its formulations advocated the establishment of world governance through supranational institutions, or the federation of the continent as a means to achieve the ultimate goal of a definitive, universal peace. This debate was reformulated by late-Enlightenment figures such as the Abbé de Saint-Pierre (1712), Rousseau (1761), Jeremy Bentham (1789), Kant (1795), or Görres (1797), who withdrew the idea of a universal monarchy or a league of kings, and opted for a federal and republican version in the form of a league of peoples, ruled by a representative assembly of nations.

This intellectual tradition was further developed at the beginning of the nineteenth century, but was now shaped by Bonapartist predominance. The Italian Piattoli and the Polish Czartoryski (1803–1805), under the auspices of the Tsar Alexander, opted for a British-Russian alliance to ensure a system respectful of liberal, pacifist, and national principles against Napoleonic expansionism. The French J.J.B. Gondon (1807), conversely, proposed a supranational government for Europe as a means of achieving civil peace and prosperity, while the Italian G. Franci still conceived in 1814 of a continent divided into four large and well-balanced empires, harmoniously coexisting. The real turning point was the project On the Reorganisation of European Society by the Count of Saint-Simon, written in 1814 during the preparations for the Congress of Vienna. In this work, Saint-Simon aimed to give an answer “to the greatest question of the moment: the European peace and regeneration”. His aim was to overcome the Westphalian system, which in his opinion was responsible for the state of war throughout the continent. The medieval and Enlightenment genre of writings on Perpetual Peace was thus still very popular in the nineteenth century, adapting to new liberal or socialist ideas, widening the European space in response to the so-called “Eastern Question” (relating to the problems caused by the instability and disintegration of the Ottoman Empire), and proposing worldwide institutions (parliaments, international courts to mediate in disputes between nations), while still respecting national identities and aiming to ensure, within the new commercial and industrial society, the end goal of international peace.

Towards the middle of the century, these utopian projects crystallised in the emergence of social movements for peace. It was certainly no coincidence that the first peace organisations were founded in Europe after the Napoleonic Wars: for example, the London Peace Society began its work in 1816 and held the first, momentous International Peace Congress in 1843. Middle-class women played a major role in these movements, introducing gendered conceptions of peace. From the mid-nineteenth century onward, the emerging labour movements (trade unions as well as socialist, social democratic, and communist parties) embraced anti-militarism as a prime political goal. This trend also held true for the European continent, where—in the context of the 1848 Revolutions which embraced the “brotherhood of nations and peoples”—the Peace Congress of 1849 took place. The congress was held in Paris and led by Victor Hugo, who, in a famous inaugural speech, claiming for the “United States of Europe”, a future “when there would be no battlefields other than those of markets opening to commerce and the minds to new ideas, and when bullets and bombs would be replaced by the force of votes of the universal suffrage.” The famous writer also attended the Peace Congress of Lugano in 1872, where, discouraged after the Franco-Prussian War, he spoke in much more pessimistic tones. The question of pacifism was hugely controversial within the German Social Democratic Party on the eve of and during the First World War—and has remained so ever since. The dispute over the war credits (1914) and the split of the party (1917) underscore the difficulty of maintaining pacifist positions in times of war and upheaval. The difficulty of maintaining pacifist positions was also evident in colonised spaces.

A cartoon in bright colours displaying two groups of people separated by a thin body of water. The group on the right is formed by five me who, as it has been written on top of each of them, and according to the stereotypical clothes and elements they wear, represent, from right to left, Portugal, Germany, France, Spain and Great Britain. This last man leans defiantly towards the men opposing them from the other side of the stream, who represent the US army, Nicaragua and Venezuela. A sign next to this second group says, NO TRESPASSAMERICA FOR AMERICANS. UNCLE SAM, and a legend on the bottom of the image reads, KEEP OFF! The Monroe doctrine must be respected.

Fig. 1: Victor Gillam, “Keep off! The Monroe Doctrine must be respected” (15 February 1896), Wikimedia Commons, https://commons.wikimedia.org/wiki/File:%22Keep_off!_The_Monroe_Doctrine_must_be_respected%22_(F._Victor_Gillam,_1896)_(with_watermark).jpg. In this political cartoon, the symbolic American figurine of Uncle Sam stands guard of American lands from both European colonisers and representatives of native South and Central American populations.

Rage for Order in the Colonies

After 1815, the European powers turned their gaze again towards overseas territories, and with more intensity. Rather than fighting among themselves, the European empires were far more inclined to cooperation, working together in the fight against piracy, slave trade, and also—later—anarchism. They invested in joint operations—a European military intervention in Syria, or joint campaigns against piracy on the open waters. Sea power was further developed to uphold the post-1815 inter-imperial order. Even though rivalries increased after this period, the cooperative spirit in Europe continued to permeate and even propel the ongoing colonial and imperialist relationships with the non-European world throughout the century.

Ford and Benton offer a convincing explanation for this imperial cooperation after 1815: the rage for order of empires, struggling not just with diverging military, commercial, and political interests, but also with the increasing importance of private investors and stakeholders, caused the state-led expansions to prioritise the juridification of colonial rule. The ‘rage for order’ was perhaps even more important as a driver for colonial expansion than open greed and exploitation. The drive for legal reform that underpinned many expeditions and invasions in colonial backwaters cannot simply be explained by pointing to the liberal type of imperialism, focusing on the advance of human rights, civilisation or other types of benevolent reforms. The mere presence of the post-1815 states (rather than their non-state, mercantile commercial predecessors) in the colonial territories drove them to more bureaucracy, more state-like procedures and institutions that needed to be established in order to settle (commercial) conflicts peacefully, or to curtail petty despots that abused their power in faraway lands.

Cooperation between states and large-scale empires also led to the proliferation of treaties, constitutions, and agreements on dividing spheres of influence. The Monroe Doctrine of 1822 issued by the US Administration, and the Nanking Treaty between Britain and the Netherlands underscore this point: these are our areas, and we determine law and order here—no other interventions or incursions allowed.

Wars of conquest in Asia (Britain, the Netherlands), the Middle East (France), and Liberation Wars (Americas) were paired with counterinsurgency campaigns, and an increase of civil wars in the wake of the nineteenth century.

With industrial warfare, European powers stepped up competition towards the end of the nineteenth century again. The opening up, exploitation, and occupation of rivers in Africa for example, led to the Conference of Berlin (1884–1885), where the principle of effective occupation precipitated the course to military action against ‘insubordinate’ colonial inhabitants. These practices of ‘permanent security’ (Dirk Moses) prompted an escalation of counterinsurgency campaigns, and already prefigured the method of concentration camps and genocidal techniques, imbued and informed by an increasing racial and biological understanding of imperial hierarchies.


In short, the long nineteenth century, which had started with the trauma of ‘total war’, secured peace on the continent and between empires for some decades. It was underpinned by new methods and means for cooperation, consultation, and deliberation, accompanied by the emergence of early peace movements and a thriving scene of pacifist thought. Yet, this cooperation led to large-scale expansive projects in overseas territories. The development of industrial warfare, of mechanised sea power, and the division of global spheres of influences, gave a new boost to imperial expansion and after 1885, increasing competition, leading up to the First World War.

Discussion questions

  1. The nineteenth century is seen as a relatively peaceful period in European history. How was this peace achieved?
  2. What was a ‘total war‘ and how did it differ from other wars?
  3. What was the ‘rage for order‘ and how does it relate to the relative peacefulness in Europe?

Suggested reading

Bell, David, The First Total War: Napoleon’s Europe and the Birth of Warfare as We Know It (London: Bloomsbury, 2007).

Benton, Lauren and Lisa Ford, Rage for Order: The British Empire and the Origins of International Law, 1800–1850 (Cambridge, MA: Harvard University Press, 2018).

de Graaf, Beatrice, Fighting Terror after Napoleon: How Europe Became Secure after 1815 (Cambridge: Cambridge University Press, 2020).

Evans, Richard, The Pursuit of Power: Europe 1815–1914 (London: Viking, 2016).

Hippler, Thomas and Miloš Vec, eds, Paradoxes of Peace in Nineteenth Century Europe (Oxford: Oxford University Press, 2015).

Klose, Fabian, In the Cause of Humanity: Eine Geschichte der humanitären Intervention im langen 19. Jahrhundert (Göttingen: Vandenhoeck & Ruprecht, 2019).

Moses, Anthony Dirk, Problems of Genocide: Permanent Security and the Language of Transgression (Cambridge: Cambridge University Press, 2021).

Robins, Nicholas A. and Adam Jones, eds, Genocides by the Oppressed: Subaltern Genocide in Theory and Practice (Bloomington: Indiana University Press, 2009).

Schroeder, Paul, The Transformation of European Politics, 1763–1848 (Oxford: Oxford University Press, 1994).

Strath, Bo, Europe’s Utopias of Peace, 1815, 1919, 1951 (London: Bloomsbury Academic, 2016).

Todd, David, ‘A French Imperial Meridian, 1814–1870’, Past & Present 210 (2011), 155–186.

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