Yisrael Meir Kagan
Rabbi Yisrael Meir Kagan (January 26, 1838 – September 15, 1933) was a rabbi in Eastern Europe who was known as the leader of of Orthodox Jewry. He also wrote very famous books, including Sefer Chofetz Chaim, and therefore, he is usually referred to as the Chofetz Chaim. He is also famous for being the rosh yeshiva of the Radin Yeshiva.