Final answer:
Otto von Bismarck was called the Iron Chancellor because of his strong and uncompromising leadership style, embracing militarism and achieving his goals through force and determination.
Step-by-step explanation:
Otto von Bismarck was called the Iron Chancellor because he was known for his strong and uncompromising leadership style. He was able to achieve his goals through force and determination, similar to iron, which is known for its strength and durability. Bismarck also embraced militarism and used military strength to achieve his political objectives.