Question: When was the leader who wanted to unify Germany (Prussia) born?

full_context: Document 1: German revolutions of 1848–49: In 1848, Austria was the predominant German state. It was considered the successor to the Holy Roman Empire, which had been dissolved by Napoleon in 1806, and was not resurrected by the Congress of Vienna in 1815.  German Austrian chancellor Klemens von Metternich had dominated Austrian politics from 1815 until 1848.
Document 2: Unification of Germany: The unification of Germany into a politically and administratively integrated nation state officially occurred on 18 January 1871, in the Hall of Mirrors at the Palace of Versailles in France. Princes of the German states, excluding Austria, gathered there to proclaim Wilhelm I of Prussia as German Emperor after the French capitulation in the Franco - Prussian War. Unofficially, the de facto transition of most of the German - speaking populations into a federated organization of states had been developing for some time through alliances formal and informal between princely rulers -- but in fits and starts; self - interests of the various parties hampered the process over nearly a century of autocratic experimentation, beginning in the era of the Napoleonic Wars, which saw the dissolution of the Holy Roman Empire of the German Nation (1806), and the subsequent rise of German nationalism.
Document 3: William I, German Emperor: William I, ( ; 22 March 1797 – 9 March 1888) of the House of Hohenzollern, was King of Prussia from 2 January 1861 and the first German Emperor from 18 January 1871 to his death, the first Head of State of a united Germany. Under the leadership of William and his Minister President Otto von Bismarck, Prussia achieved the unification of Germany and the establishment of the German Empire. Despite his long support of Bismarck as Minister President, William held strong reservations about some of Bismarck's more reactionary policies, including his anti-Catholicism and tough handling of subordinates. In contrast to the domineering Bismarck, William was described as polite, gentlemanly and, while staunchly conservative, more open to certain classical liberal ideas than his grandson Wilhelm II.
Document 4: Territorial evolution of Germany: The territorial changes of Germany include all changes in the borders and territory of Germany from its formation in 1871 to the present. Modern Germany was formed in 1871 when Otto von Bismarck unified most of the German states, with the notable exception of Austria, into the German Empire. After the First World War, Germany lost about 10% of its territory to its neighbours and the Weimar Republic was formed. This republic included territories to the east of today's German borders.
Document 5: History of colonialism: Africa was the target of the third wave of European colonialism, after that of the Americas and Asia. Many European statesmen and industrialists wanted to accelerate the Scramble for Africa, securing colonies before they strictly needed them. As a champion of Realpolitik, Bismarck disliked colonies and thought they were a waste of time, but his hand was forced by pressure from both the elites and the general population which considered the colonization a necessity for German prestige. German colonies in Togoland, Samoa, South - West Africa and New Guinea had corporate commercial roots, while the equivalent German - dominated areas in East Africa and China owed more to political motives. The British also took an interest in Africa, using the East Africa Company to take over what are now Kenya and Uganda. The British crown formally took over in 1895 and renamed the area the East Africa Protectorate.
Document 6: Imperialism: However, in 1883–84 Germany began to build a colonial empire in Africa and the South Pacific, before losing interest in imperialism. Historians have debated exactly why Germany made this sudden and short-lived move.[verification needed] Bismarck was aware that public opinion had started to demand colonies for reasons of German prestige. He was influenced by Hamburg merchants and traders, his neighbors at Friedrichsruh. The establishment of the German colonial empire proceeded smoothly, starting with German New Guinea in 1884.
Document 7: Franco-Prussian War: According to some historians, Bismarck adroitly created a diplomatic crisis over the succession to the Spanish throne, then edited a dispatch about a meeting between King William of Prussia and the French ambassador, to make it appear that the French had been insulted. The French press and parliament demanded a war, which the generals of Napoleon III assured him that France would win. Napoleon and his Prime Minister, Émile Ollivier, for their parts sought war to solve their problems with political disunity in France. On 16 July 1870, the French parliament voted to declare war on the German Kingdom of Prussia and hostilities began three days later. The German coalition mobilised its troops much more quickly than the French and rapidly invaded northeastern France. The German forces were superior in numbers, had better training and leadership and made more effective use of modern technology, particularly railroads and artillery.
Document 8: Napoleon: After Austerlitz, Napoleon established the Confederation of the Rhine in 1806. A collection of German states intended to serve as a buffer zone between France and Central Europe, the creation of the Confederation spelled the end of the Holy Roman Empire and significantly alarmed the Prussians. The brazen reorganization of German territory by the French risked threatening Prussian influence in the region, if not eliminating it outright. War fever in Berlin rose steadily throughout the summer of 1806. At the insistence of his court, especially his wife Queen Louise, Frederick William III decided to challenge the French domination of Central Europe by going to war.
Document 9: Unification of Germany: Historians debate whether Otto von Bismarck -- Minister President of Prussia -- had a master plan to expand the North German Confederation of 1866 to include the remaining independent German states into a single entity or simply to expand the power of the Kingdom of Prussia. They conclude that factors in addition to the strength of Bismarck's Realpolitik led a collection of early modern polities to reorganize political, economic, military, and diplomatic relationships in the 19th century. Reaction to Danish and French nationalism provided foci for expressions of German unity. Military successes -- especially those of Prussia -- in three regional wars generated enthusiasm and pride that politicians could harness to promote unification. This experience echoed the memory of mutual accomplishment in the Napoleonic Wars, particularly in the War of Liberation of 1813 -- 14. By establishing a Germany without Austria, the political and administrative unification in 1871 at least temporarily solved the problem of dualism.
Document 10: Imperialism: Not a maritime power, and not a nation-state, as it would eventually become, Germany’s participation in Western imperialism was negligible until the late 19th century. The participation of Austria was primarily as a result of Habsburg control of the First Empire, the Spanish throne, and other royal houses.[further explanation needed] After the defeat of Napoleon, who caused the dissolution of that Holy Roman Empire, Prussia and the German states continued to stand aloof from imperialism, preferring to manipulate the European system through the Concert of Europe. After Prussia unified the other states into the second German Empire after the Franco-German War, its long-time Chancellor, Otto von Bismarck (1862–90), long opposed colonial acquisitions, arguing that the burden of obtaining, maintaining, and defending such possessions would outweigh any potential benefits. He felt that colonies did not pay for themselves, that the German bureaucratic system would not work well in the tropics and the diplomatic disputes over colonies would distract Germany from its central interest, Europe itself.
Document 11: Germans: In 1870, after France attacked Prussia, Prussia and its new allies in Southern Germany (among them Bavaria) were victorious in the Franco-Prussian War. It created the German Empire in 1871 as a German nation-state, effectively excluding the multi-ethnic Austrian Habsburg monarchy and Liechtenstein. Integrating the Austrians nevertheless remained a strong desire for many people of Germany and Austria, especially among the liberals, the social democrats and also the Catholics who were a minority within the Protestant Germany.
Document 12: Germans: In 1866, the feud between Austria and Prussia finally came to a head. There were several reasons behind this war. As German nationalism grew strongly inside the German Confederation and neither could decide on how Germany was going to be unified into a nation-state. The Austrians favoured the Greater Germany unification but were not willing to give up any of the non-German-speaking land inside of the Austrian Empire and take second place to Prussia. The Prussians however wanted to unify Germany as Little Germany primarily by the Kingdom of Prussia, whilst excluding Austria. In the final battle of the German war (Battle of Königgrätz) the Prussians successfully defeated the Austrians and succeeded in creating the North German Confederation.
Document 13: Imperialism: From their original homelands in Scandinavia and northern Europe, Germanic tribes expanded throughout northern and western Europe in the middle period of classical antiquity; southern Europe in late antiquity, conquering Celtic and other peoples; and by 800 CE, forming the Holy Roman Empire, the first German Empire. However, there was no real systemic continuity from the Western Roman Empire to its German successor which was famously described as "not holy, not Roman, and not an empire", as a great number of small states and principalities existed in the loosely autonomous confederation. Although by 1000 CE, the Germanic conquest of central, western, and southern Europe (west of and including Italy) was complete, excluding only Muslim Iberia. There was, however, little cultural integration or national identity, and "Germany" remained largely a conceptual term referring to an amorphous area of central Europe.
Document 14: Germans: The Napoleonic Wars were the cause of the final dissolution of the Holy Roman Empire, and ultimately the cause for the quest for a German nation state in 19th-century German nationalism. After the Congress of Vienna, Austria and Prussia emerged as two competitors. Austria, trying to remain the dominant power in Central Europe, led the way in the terms of the Congress of Vienna. The Congress of Vienna was essentially conservative, assuring that little would change in Europe and preventing Germany from uniting. These terms came to a sudden halt following the Revolutions of 1848 and the Crimean War in 1856, paving the way for German unification in the 1860s. By the 1820s, large numbers of Jewish German women had intermarried with Christian German men and had converted to Christianity. Jewish German Eduard Lasker was a prominent German nationalist figure who promoted the unification of Germany in the mid-19th century.
Document 15: Franco-Prussian War: The creation of a unified German Empire ended the balance of power that had been created with the Congress of Vienna after the end of the Napoleonic Wars. Germany had established itself as the main power in continental Europe with the most powerful and professional army in the world.[citation needed] Although Great Britain remained the dominant world power, British involvement in European affairs during the late 19th century was very limited, allowing Germany to exercise great influence over the European mainland.[citation needed] Besides, the Crown Prince's marriage with the daughter of Queen Victoria was only the most prominent of several German–British relationships.
ground_truth: 1862
sub_queries: who was the leader who wanted to unify germany (prussia) Answer: Otto von Bismarck
When was Otto von Bismarck born? Answer: 1862