Franco-Prussian War: the conflict that plunged Europe into a nightmare

Emperor Napoleon III was primarily responsible for this disaster. A nephew of the great Napoleon who had conquered most of Europe, Napoleon III had made himself emperor of the French following a coup in 1852. Victor Hugo famously dismissed him as “Napoleon the Small”, but the French people expected great things of him. Nor were his achievements negligible: he rebuilt Paris, creating the city we know today; and he reasserted French pre-eminence by defeating the Russians (with British help) in the Crimean War of 1853–56, and the Austrians in 1859, allowing for Italian unification.

Napoleon III was mid-19th-century Europe’s great disruptor. Unfortunately for him, and for France, an even greater disruptor emerged east of the Rhine, in the large German state of Prussia. His name was Otto von Bismarck.

When Bismarck became prime minister in 1862, Prussia was the weakest of Europe’s ‘great’ powers, just one of a patchwork of states that were yet to coalesce into the German empire. But its king, William I, was determined to rectify this through far-reaching military reforms, and appointed the maverick Bismarck to ram them through a reluctant Prussian parliament. Upon his appointment, Bismarck made his views clear in one of history’s more famous soundbites: “The great questions of the day are not decided through speeches and majorities but by iron and blood.”

Bismarck and Napoleon had a great deal in common. Both were conservative populists, and both recognised that the new force of nationalism sweeping Europe was something to be exploited rather than feared. Yet their attempts to harness this nationalist fervour set them on a collision course, one that would end in conflict.

Both Napoleon and Bismarck believed that nationalism was something to be exploited rather than feared

The Franco-Prussian War, as that conflict is now known, was over in 10 short months, but its consequences were extraordinarily long-reaching. In a victorious and newly unified Germany, it helped make militarism the dominant ideology; in a defeated and humiliated France, it fostered a seething desire for revenge. These toxic ingredients set the scene for further bouts of bloodletting – on a far greater scale – in the following century. It’s surely safe to say that without Napoleon and Bismarck’s battle for supremacy in 1870, Europe’s 20th century would have followed a very different trajectory indeed.

Napoleon’s wake-up call

The countdown to the Franco-Prussian War started with another war: that of 1866, when Prussia’s newly reformed army crushed Austria in seven weeks. This vindicated Bismarck at home and was a wake-up call to Europe. Prussia became the dominant power in central Europe and the other German states now looked to Berlin, not Vienna, for leadership.

This terrified France. Napoleon III’s initial panic response was to re-establish French prestige by annexing Luxembourg or even Belgium. He sought Bismarck’s agreement, but was rebuffed. Then, in 1868, a new European crisis started with the overthrow of Spain’s Queen Isabella II. Spain needed a new monarch and, as was often the case in this period, chose a member from one of Germany’s innumerable princely houses. Unfortunately that choice, Prince Leopold of Hohenzollern, was related to Prussia’s William. Not surprisingly, France went ballistic when this knowledge went public in July 1870. Napoleon III’s government, goaded by domestic opinion, tried to save face by forcing Prussia into vetoing the arrangement. King William was happy to oblige the French, as he had never liked the prospect of a close relative ruling an unstable country like Spain.

There things might have rested, but for the French then overplaying their hand. The French ambassador to Prussia met William at the spa resort of Bad Ems (13 July) and attempted to force a public climbdown, pressing him to block any future Hohenzollern candidacy. This backfired when William politely rebuffed the ambassador.

Bismarck was not present at Bad Ems, but had remained in Berlin, where an account of the exchange reached him in the so-called Ems telegram. Bismarck, in full knowledge of the likely consequences, then edited the telegram, deleting the diplomatic niceties, and released it for publication in the international press. This was Bismarck’s famous red rag, waved at the Gallic bull. The French duly rose to the bait and declared war, amid feverish jubilation on the streets of Paris.

The Franco-Prussian War, despite its name, saw France pitted against a coalition of German states who sided with Prussia. Their inhabitants increasingly saw themselves as fellow Germans and viewed the war against France as a national crusade. Prussia nonetheless provided the overwhelming majority of German forces, as well as the military leadership.

In technological terms, there was little between the belligerents: the French had better infantry rifles, the Prussians superior artillery. What gave the Prussians a decisive advantage was their numerical superiority at the outset, gained by very fast mobilisation, and above all superior military leadership.

“No battle plan ever survives contact with the enemy.” So stated Helmuth von Moltke, the Prussian commander in 1870. Moltke was a new kind of military leader, more manager than charismatic warlord. He presided over the Prussian General Staff, an institution that planned operations and contingencies in peacetime. The regular rotation of staff officers back to their regiments ensured that best practice was spread throughout the army, which meant the overall commander could safely delegate to those best placed to seize opportunities that unfolded once hostilities commenced. This was the answer to the problem highlighted in Moltke’s quote above. Neither the French, nor other armies, operated in this way, and this showed in 1870.

Superior planning and numbers allowed the Prussians to concentrate along France’s eastern frontier. The French, without proper plans, quickly suffered setbacks and these destroyed the morale of Napoleon III, who had unwisely assumed personal command. The only sensible option for the French was to fall back and regroup, but Napoleon could not afford to lose face by retreating. The consequence was a series of major French defeats, starting with Gravelotte-St Privat on 18 August. This would prove the bloodiest engagement of the war, with a casualty rate that was a portent of 20th-century horrors. In just one 20-minute period, the Prussian Guard Corps alone suffered 8,000 men killed or wounded, due to an unholy combination of fast, modern weaponry and outdated attack styles involving massed ranks of men. At least the widespread introduction in this war of ‘dog tags’ – discs worn by soldiers that included their basic details – allowed for the identification of the dead.

Despite horrific losses at Gravelotte-St Privat, the Prussians won, thanks to superior artillery and better manoeuvring. Moltke then trapped most of the French army in the fortress of Metz. Political pressures intervened again on the French side and demanded a rescue effort. This resulted in the battle of Sedan (1–2 September), a second catastrophic French defeat in which Napoleon III himself was captured. News of this debacle reached Paris a few days later and caused regime change. The new republican Government of National Defence filled the political vacuum and proclaimed a war of national resistance.

In just one 20-minute period, the Prussian Guard Corps alone suffered 8,000 men killed or wounded

The Franco-Prussian War now entered a new phase. Prussian forces advanced on Paris, which they besieged from 19 September. The French capital was too strong to be taken by storm, so needed to be starved into submission. While Léon Gambetta escaped to the provinces and raised new armies, irregular volunteers, known as Francstireurs, engaged in guerrilla tactics. The Prussians did not recognise them as legitimate combatants and shot them upon capture, burning down villages suspected of harbouring them.

This messy, dirty war dragged on for the remainder of 1870, to the discomfort of Bismarck who feared international opinion was swinging in favour of France. However, the defeat of Gambetta’s new armies in December meant that Paris was not going to be relieved, and with food running out there was no option but to seek a truce (28 January 1871) which ended the fighting. This created the conditions for French elections to be held, which produced a government with the authority to conclude a preliminary peace on 26 February. Though the new regime’s grip on power was threatened by the so-called Paris Commune, which briefly seized control of the capital in March, it nonetheless ratified the definitive Treaty of Frankfurt on 10 May.

Militarism off the leash

Few who ratified the Treaty of Frankfurt could have guessed the immense impact that the Franco-Prussian War would have on the continent of Europe – an impact that was, in the estimation of future British prime minister Benjamin Disraeli, greater than the French Revolution. Geopolitically, Europe went from having a ‘soft’ centre, made up of lots of small separate states, to one with a hard core: impressed by Prussia’s military leadership, and driven by public opinion, Germany’s smaller states agreed to cede their independence to Berlin and form a single entity, the German empire. The big question that arose – and persists – is how such a powerful state can operate within the wider family of European nations.

Disraeli argued that the Franco-Prussian War had a greater impact on Europe than the French Revolution

Initially, things worked well enough. Bismarck used his undoubted political talents to preserve peace. However, when he fell from power in 1890, the more pernicious legacies of the 1870 war came to the fore, including militarism. All major powers in the late 19th century were militaristic, but newly unified Germany was more so than most. Prussia’s army, which formed the core of Germany’s military, emerged from the 1870 war with immense prestige. With Bismarck gone, no civilian leader had the stature to challenge its primacy. In Germany and across Europe, the military planner was let off the leash.

For France, defeat came as an awful shock made worse by the harsh treaty that followed, which inflicted the loss of the region of Alsace and part of Lorraine, and the payment of a large reparations bill. This humiliation nurtured a desire for revenge. A generation of schoolchildren grew up taught of the injustices of the peace settlement. In the 1890s, France exploited wider European unease at German power by creating an alliance, which in turn made Germany feel cornered.

• La débâcle! The aftermath of the Franco-Prussian War

This combination of militarism and bitterness created the perfect conditions for the next round of Franco-German conflict, the First World War, which on this occasion dragged in the rest of the world. Tragically, the millions of lives lost between 1914 and 1918 resolved nothing – and it was only after countless more died in the Second World War that the architects of Franco-German reconciliation built an edifice that still dominates Europe’s political landscape.

Chief among these architects were West Germany’s chancellor Konrad Adenauer and French president Charles de Gaulle. Both had fathers who fought in the Franco-Prussian War. Both originated from regions that bordered each other’s nations, and which had been contested throughout the centuries. There may or may not have been a sentimental dimension to their thinking.

The two statesmen also calculated that partnership within a European framework would enhance their ability to influence world events now largely shaped by the two new superpowers, America and the Soviet Union. This is what Adenauer meant when he told one of his French interlocutors that “Europe will be your revenge” shortly after the Suez debacle of 1956, when the US forced France and Britain to back down.

Both de Gaulle and Adenauer recognised the futility of the cycle of Franco-German wars initiated a century previously, and on 22 January 1963 concluded the Élysée Treaty, ushering in a new period of Franco-German friendship. Within this treaty’s framework other initiatives have flowed, designed to extend the relationship from the level of the state to society more broadly, through ideas such as youth exchanges, town twinning and joint history textbooks for schoolchildren. Within these textbooks, the Franco-Prussian War is not forgotten, but rather treated as a shared historical experience.

For Europe more broadly, including Britain, the Franco-German partnership as it now stands raises its own questions. Other European countries fear marginalisation when key decisions are essentially agreed beforehand by Paris and Berlin. Deeper integration is proposed as the best way of empowering these other states, and at the same time resolving the issue first created in 1870: how to run a continent with such a hard core. However, this integration process has spawned its own set of problems. Seen in these terms, it is clear that the legacy of the 1870 war still helps determine our continent’s everyday politics and will continue to do so for the foreseeable future.

Michael Rowe is reader in European history at King’s College London

This article was first published in the November 2020 edition of BBC History Magazine