Otto von Bismarck was determined to create the German Empire. His main strategy for accretion of the states in his path was war- to seize the enemy on their own land without major concern for consequences. He preyed upon problems between Prussia and its surrounding countries, taking advantage of weaknesses until the countries fell into his trap and unified to survive. Bismarck's first attempt at this was with Denmark, which violated a treaty it had with Prussia. Then, Bismarck attacked Austria, in which he turned against his former ally and crushed its supposed attempt at becoming larger and more powerful than Germany. Bismarck's unyielding drive and sharp mind able to take advantage of weaknesses without guilt led to German unification through the Austro-Prussian and Danish-Prussian wars.
Bismarck in his seizure of Denmark's Holstein and Schleswig perhaps had a sound case. The Treaty of London in 1852 guaranteed to Prussia that the duchies of Holstein and Schleswig, both of which lay on German territory, would not be annexed into Denmark. Going against the treaty, King Christian assumed that because Schleswig was mostly Dutch, he had the right to annex it. The German minority in the area spoke up and their counterparts in mainland Germany voiced their opposition. Bismarck was unhappy about this not only because Denmark failed to adhere to the treaty in place, but also because he had specific plans for the areas because of their specific location. Prussia's potential alliance with Austria came into play at this point, for two reasons, the first being to ensure their cooperation with Prussia to make the next war a bit easier and second to further strengthen their somewhat weak army. Because the areas were mostly Danish (thus King Christian's desire to annex them), there was great pull on both sides to end the conflict. Prussia ultimately decided to take on Austria as an ally. An ultimatum was presented- Denmark would remove its army from Prussian territory in...