March 22, 1797 - March 9, 1888: Age 90
The first Kaiser Wilhelm lived to be 90; if he had died sooner, the history of Europe and, indeed, the world, might have been very different.
Wilhelm began life as a prince, the younger son of King Friedrich Wilhelm III of Prussia. His brother inherited the crown in 1840 but was incapacitated by a stroke in 1857 dying a few years later. Thus Wilhelm found himself King of Prussia and, in 1862, appointed Otto von Bismarck prime minister, with a mandate to implement the conservative politics he favoured.
Bismarck was a genius whose life's ambition was to unify the German states into a world superpower, and in less than a decade he had succeeded completely, using fear of socialism and hatred for the French as goads to consolidate Wilhelm's power. Wilhelm became the first German Emperor in 1870.
Wilhelm was extremely conservative, and the German state was effectively a military regime in which the acquisition and maintenance of superior armies was paraamount. His son, Crown Prince Friedrich, dreamed of modernizing the German state, creating a (relatively) liberal society modeled on the British Empire. He was greatly influenced by his wife, the daughter of Queen Victoria, an intelligent and passionate liberal. He opposed Bismarck's politics of fear, but since Bismarck ruled through his father, it seemed it was only a matter of time before Friedrich would ascend the throne and begin to realize his dream.
Wilhelm, however, lived on. And on. He became confused and weak in his old age, giving Bismarck complete liberty to aggressively pursue his reactionary policies. Moreover Bismarck, with a keen eye to the future, was actively cultivating the esteem of Friedrich's son, the future Wilhelm II. He played on tensions between father and son in both generations, wisely making no attempt to appease Friedrich while manipulating the elder Wilhelm and seducing the younger one.
Bismarck's bet paid off: by the time Wilhelm finally died at age 90, Friedrich was already dying of cancer. He ruled for just 99 days, and was succeeded by a young, brash, aggressive Wilhelm II.
Bismarck anticipated that his influence over the throne could thus continue unabated, but in the end Wilhelm's megalomania pushed him beyond even Bismarck's reach. Although the causes of World War I are complex, there is no doubt that the aggressive and often foolish policies of Wilhelm II were a very big factor in pushing Europe into a state of total war.