Conversation so far:
who was known as the man of blood and iron in world history
Otto von Bismarck, the Chancellor of Prussia and Germany, was called “man of blood” from his great war policy, and “iron” from his indomitable will.
when did otto von bismarck serve as chancellor of germany
Otto von Bismarck was in office as Chancellor of the German Empire from 21 March 1871 through 20 March 1890

Question: how about as minister president
Self-contained rewrite: when did otto von bismarck serve as minister president of prussia