The German Empire (German: Deutsches Kaiserreich), variously referred to as the German Reich or Realm, the Second Reich, or Imperial Germany, was the historical German nation state that existed from the unification of Germany in 1871 to the abdication of Kaiser Wilhelm II in November 1918, when Germany became a federal republic.
The German Empire consisted of 27 constituent territories, with most of them being ruled by royal families. This included 4 kingdoms, 6 grand duchies, 6 duchies (5 after 1876), 7 principalities, 3 free hanseatic cities, and 1 imperial territory. While the Kingdom of Prussia contained most of the population and most of the territory of the empire, the Prussian leaders were supplanted by leaders from all over Germany, and Prussia itself played a lesser role. As Dwyer (2005) points out, Prussia's "political and cultural influence had diminished considerably" by the 1890s. The German Empire's three largest neighbours were all rivals: Imperial Russia to the east, France to the west, and Austria-Hungary, a rival but also an ally, to the south-east.
After 1850, the states of Germany had rapidly become industrialized, with particular strengths in coal, iron (and later steel), chemicals, and railways. In 1871, when the new German Empire was created, it had a population of 41 million people, and by 1913 this had increased to 68 million. A heavily rural collection of states in 1815, the united Germany became predominantly urban. During its 47 years of existence, the German Empire operated as an industrial, technological, and scientific giant, gaining more Nobel Prizes in science than Britain, France, Russia, and the United States combined.
Germany became a great power, boasting a rapidly growing rail network, the world's strongest army, and a fast-growing industrial base. In less than a decade, itsnavy went from being a negligible force to one which was second only to the Royal Navy. After the removal of the powerful Chancellor Otto von Bismarck in 1890 (following the deaths of two Emperors, Wilhelm I and Frederick III, in 1888), the young Emperor Wilhelm II engaged in increasingly reckless foreign policies that left the Empire isolated. Its network of small colonies in Africa and the Pacific paled in comparison to the British and French empires, and only a small number became profitable. When the great crisis of 1914 arrived, the German Empire had only one ally, being Austria-Hungary, a great power at the time. They were later joined by the Ottoman Empire and Bulgaria.
In the First World War, German plans to capture Paris quickly in autumn 1914 failed, and the war on the Western Front, against the forces of the British Empire and France, became a stalemate. The Allied naval blockade made for increasing shortages of food, and Germany was repeatedly forced to send troops to bolster Austria and Turkey on other fronts. However, Germany had great success on the Eastern Front; as a result of the Communists' determination to end Russian involvement in the war, it carved out large Eastern territories following the Treaty of Brest-Litovsk. German declaration of unrestricted submarine warfare in early 1917 was designed to strangle the British; it failed, because of the use of a trans-Atlantic convoy system. But the declaration—along with the Zimmermann Telegram—did bring the United States into the war, with its large reserves of money, food, armaments, and soldiers. Meanwhile, German civilians and soldiers had become war-weary and radicalised by the Russian Revolution.
The high command under Paul von Hindenburg and Erich Ludendorff increasingly controlled the country, as they gambled on one last offensive in spring 1918 before the Americans could arrive in force, using large numbers of troops and guns withdrawn from the Eastern Front. This failed, and by October the armies had been in retreat since August, the Austro-Hungarian Empire and the Ottoman Empire had collapsed, and the German people had lost faith in their political system. The Empire collapsed in the November 1918 Revolution, as the Emperor and all the ruling kings, grand-dukes and sovereign dukes and princes abdicated, and a republic took over.