Years: 1870–1936
Primary city: Aleksotas
Rabbi Baruch Horowitz was a leading figure of the Lithuanian yeshiva world, connected through marriage to the Frank family of Aleksot, patrons of the Mussar movement and financial supporters of the Slabodka Yeshiva. He served concurrently as Rav of Aleksot and as Rosh Yeshiva of the Slabodka Yeshiva (Knesses Yisrael). He rose to the chairmanship and later the presidency of the Agudas HaRabbonim of Lithuania, succeeding his brother-in-law Rabbi Moshe Mordechai Epstein. Following Rabbi Epstein's departure for Chevron in the mid-1920s, Rabbi Horowitz assumed primary stewardship of the Slabodka Yeshiva alongside Rabbi Yitzchak Yitzchak Sher, preserving its Mussar character and working to maintain the yeshiva's independence.