Yahrtzeit of Rabbi Aharon Kotler (1892-1962), a prominent Torah sage in Lithuania, and later in America. Rabbi Kotler studied under the famed Alter of Slabodka, and was the son-in-law of Rabbi Isser Zalman Meltzer. Rabbi Kotler led various efforts to rescue Jews from the Holocaust; he was instrumental in persuading Henry Morgenthau, U.S. Treasury Secretary, to risk his political career in order to help save Jews. In 1943, Rabbi Kotler founded a yeshiva in Lakewood, New Jersey, which has since grown into the largest institution of its kind in America with over 5,000 advanced-level students.