When Bismarck was appointed Prussian chancellor in 1862 by King Wilhelm IV, The democratic attempt of unifying Germany had failed and there was widespread sentiment among the Germans in favour of unification. There were a number of obstacles in Prussia's way of unifying Germany. Among them were foreign powers' interests in Germany, In other words, In order for Bismarck to unify Germany he had to eliminate all the other powers that posed a threat to German unification. Since the political approach had failed, Bismarck adopted a policy of "blood and Iron" for his plans of unifying Germany. Bismarck was a cunning politician who always made the other side seem the aggressor and in this way always appeared the victim. By manipulating political situations, Bismarck succeeded in going to war, and defeating, all the counties that stood the way of a united Germany under Prussian rule.
Bismarck's first step was to gain as much support and trust of other countries before trying to eliminate the big threats e.g.
France. In 1863 Bismarck saw an opportunity to gain Russia's friendship. The Polish were revolting against Russia and Bismarck promised the Tsar his support and massed troops on the frontier to prevent the Polish from crossing it, Thus helping Russia and gaining her support for future wars.
The next step was manipulating a situation in Denmark to eventually eliminate Austria.
The Danish king, Frederick VII tried to, against the congress of Vienna, incorporate Schleswig and Holstein into Denmark. He did not succeed and The Salic law of succession was passed. After Frederick VII, Christian IX came to power and he also tried to take over these countries, this time succeeding. Now Bismarck saw an opportunity, he appealed to Austria to help Prussia to Drive the Danes out of Schleswig and Holstein, the reason...