After the failure of the Frankfurt Constitution it slowly became clear to far-sighted Germans that there was only one way in which German unity could come about.  If, unlike the separate provinces of Canada and South Africa, the German States would not voluntarily sink their identity in a larger whole, unity could only come through their acceptance of the supremacy of one of the existing States.

There were only two possible candidates for the supremacy, Austria and Prussia.  Austria was still, at that time, as she had been for centuries, in a position of undisputed headship.  But her German policy was always hampered because she had also to consider her non-German subjects.  Prussia, a younger and more homogeneous State, with a better organised administration and a better disciplined people, was preparing to assert herself.  In 1862, at a moment when liberalism was gathering strength in Prussia, Count Bismarck became chief Minister of the Prussian Crown and the dominating force in Prussian policy.  Bismarck was a Conservative and a reactionary, wholly out of sympathy with the ideals of 1848.  His immediate object was to secure the supremacy of Prussia among the German States.  In the very first months of his leadership he made it clear, in a famous sentence, by what methods he hoped to achieve his end.  “The great questions are to be settled,” he told the Prussian Diet, with a scornful hit at the Confederation, “not by speeches and majority resolutions, but by blood and iron.”

He was not long in translating words into action.  In 1864 the King of Denmark died, and difficulties at once arose as to the succession to the Duchies of Schleswig and Holstein, which still belonged to the German Confederation.  Austria and Prussia intervened jointly in the name of the Confederation, and, as a result, the Duchies were separated from Denmark, Schleswig being administered by Austria and Holstein by Prussia.  The object of this rather clumsy plan, which originated with Bismarck, was to create difficulties which would enable him to pick a quarrel with Austria.  In 1866 this manoeuvre proved successful.  Bismarck goaded Austria into war and succeeded, after a six weeks’ campaign, in expelling her from the German State system, following this up by rounding off her own dominions with the annexation of a number of the smaller pro-Austrian States, amongst them the kingdom of Hanover.  His victory also had the effect of completely checking the growing agitation for the establishment of responsible government in Prussia.[1]

[Footnote 1:  On this point see Bismarck’s Recollections, and the good short account in Powicke’s Bismarck.]

Having made Prussia supreme in Germany, Bismarck was now in a position to solve the problem of German unity.  He resolved to employ the same well-tried method.  In 1870 the somewhat high-handed manner of Napoleon III. made it possible for him to bring about a war between the German States and France, in which Germany, under Prussian leadership, was completely victorious.  In the flush of their success, after the capture of Paris in January 1871, the lesser States of Germany agreed to enter into a Federal Union under Prussian supremacy and to accept the King of Prussia as its head, with the title of Emperor.