Rav Yosef Yitzchok Schneerson Rebbe of Avritsh

Rav Yosef Yitzchok of Avritsh was the son of the Tzemach Tzedek of Lubavitch, and father in law of Rav Shalom DovBer, also known as the Rebbe RaShaB of Lubavitch, Rav Yosef Yitzchok's daughter Rebbetzin Shterna Sara, was the wife of the Rebbe RaShaB.