Final answer:
Kaiser Wilhelm I appointed Otto von Bismarck as prime minister and tasked him with strengthening Prussia's military and expanding its power. Bismarck used war to unite the German states, leading to the formation of the German Empire. However, Wilhelm II dismissed Bismarck and pursued a more aggressive foreign policy.
Step-by-step explanation:
The relationship between Kaiser Wilhelm I and Chancellor Otto von Bismarck was complex. Wilhelm I appointed Bismarck as prime minister in 1862 and tasked him with strengthening Prussia's military and expanding its power. Bismarck used war as a means to unite the German states under Prussia's leadership, ultimately leading to the formation of the German Empire. However, Wilhelm II, who took the imperial throne after Wilhelm I, dismissed Bismarck in 1890 and pursued a more aggressive foreign policy, aiming to make Germany a colonial empire.