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
when did otto von bismarck serve as minister president of prussia
Otto von Bismarck was in office as Minister President of Prussia from 9 November 1873 to 20 March 1890
when did otto von bismarck make his famous speech
Prussian Prime Minister Otto von Bismarck delivered his famous Blood and Iron speech at a meeting of the budget commission of the Prussian Parliament on September 30, 1862.

Question: what is the prime minister known for
Self-contained rewrite: what is otto von bismarck known for