Firstly, the Crimean War has caused the collapsing of the Congress of Vienna, which in turn resulted, to having 'freed' individual small German states to be on their own. This factor created a window of opportunity to Prussia and Bismarck as the small states could be easily brought under the Prussian Empire, if necessary with the help of the Prussian Army. An example of how Prussia's strategy worked was when trying to get Schleswig-Holstein to be part of Prussia. Bismarck uses the opportunity at hand to get hold of new German territories by convincing William I to do so and by initially getting Austria to go against Denmark. The disagreement between Austria and Prussia led to the Austro-Prussian war in 1866.
Prussia reign supreme in the 1866 war due chiefly to the efforts of Helmuth von Moltke on his expertise on military logistics and Albert von Roon the minister of war (when Bismark was in power.) with the help of industrialisation. By making use of the railway system, the telegraph and the needle-gun, the Prussian army was one of the most modernised forces and thus, one of the strongest at that point in time. The two military duo were the caused for the victorious war of 1866 as mentioned and the Franco-Prussian war in1870. Both of these wars were significant in a sense that both created a kind of stepping stone for the unification.
The unification of Germany was also made possible owing to the fact that under Bismarck, the Treaty of Prague was signed between Prussia and Austria stating that Prussia and all the German states north of river Main were to be under the North German Confederation, creating a single unit and more importantly, leaving only three German states left to be annexed before Germany could truly be unified.
The final phase of unification took place when there was a strong...