This article covers worldwide diplomacy and, more generally, the international relations of the great powers from 1814 to 1919. This era covers the period from the end of the Napoleonic Wars and the Congress of Vienna (1814–1815), to the end of the First World War and the Paris Peace Conference (1919–1920).
Important themes include the rapid industrialization and growing power of Great Britain, the United States, France, Prussia/Germany, and, later in the period, Italy and Japan. This led to imperialist and colonialist competitions for influence and power throughout the world, most famously the Scramble for Africa in the 1880s and 1890s; the reverberations of which are still widespread and consequential in the 21st century. Britain established an informal economic network that, combined with its colonies and its Royal Navy, made it the hegemonic nation until its power was challenged by the united Germany. It was a largely peaceful century, with no wars between the great powers, apart from the 1853–1871 interval, and some wars between Russia and the Ottoman Empire. After 1900, there was a series of wars in the Balkan region, which exploded out of control into World War I (1914–1918) — a massively devastating event that was unexpected in its timing, duration, casualties, and long-term impact.
In 1814, diplomats recognized five great powers: France, Britain, Russia, Austria (in 1867–1918, Austria-Hungary) and Prussia (in 1871–1918, the German Empire). Italy was added to this group after its unification in 1860 ("Risorgimento"); by 1905 two rapidly growing non-European states, Japan and the United States, had joined the great powers. Romania, Bulgaria, Serbia, and Montenegro initially operated as autonomous vassals, for until about 1908–1912 they were legally still part of the declining Ottoman Empire, before gaining their independence.
In 1914, on the eve of the First World War, there were two major blocs in Europe: the Triple Entente formed by France, Britain, and Russia and the Triple Alliance formed by Germany, Austria-Hungary, and Italy. Italy stayed neutral and joined the Entente in 1915, while the Ottoman Empire and Bulgaria joined the Central Powers. Neutrality was the policy of Belgium, the Netherlands, Luxembourg, Denmark, Sweden, Norway, Greece, Portugal, Spain, and Switzerland. The First World War unexpectedly pushed the great powers' military, diplomatic, social and economic capabilities to their limits. Germany, Austria–Hungary, and the Ottoman Empire were defeated; Germany lost its great power status, and the others were broken up into collections of states. The winners Britain, France, Italy and Japan gained permanent seats at the governing council of the new League of Nations. The United States, meant to be the fifth permanent member, decided to operate independently and never joined the League.
For the following periods, see diplomatic history of World War I and international relations (1919–1939).
1814–1830: Restoration and reaction
As the four major European powers (Britain, Prussia, Russia, and Austria) opposing the French Empire in the Napoleonic Wars saw Napoleon's power collapsing in 1814, they started planning for the postwar world. The Treaty of Chaumont of March 1814 reaffirmed decisions that had been made already and which would be ratified by the more important Congress of Vienna of 1814–15. They included the establishment of a German Confederation including both Austria and Prussia (plus the Czech lands), the division of French protectorates and annexations into independent states, the restoration of the Bourbon kings of Spain, the enlargement of the Netherlands to include what in 1830 became modern Belgium, and the continuation of British subsidies to its allies. The Treaty of Chaumont united the powers to defeat Napoleon and became the cornerstone of the Concert of Europe, which formed the balance of power for the next two decades.
One goal of diplomacy throughout the period was to achieve a "balance of power", so that no one or two powers would be dominant. If one power gained an advantage—for example by winning a war and acquiring new territory—its rivals might seek "compensation"—that is, territorial or other gains, even though they were not part of the war in the first place. The bystander might be angry if the winner of the war did not provide enough compensation. For example, in 1866, Prussia and supporting north German States defeated Austria and its southern German allies, but France was angry that it did not get any compensation to balance off the Prussian gains.