Complex sentence: Novardok yeshiva was re-established in Białystok under the leadership of the Alter's son-in-law, Rabbi Avraham Yoffen, it soon became the center of an entire movement.
Split into simpler sentences: Novardok yeshiva was re-established in Białystok under the leadership of the "Alter's" son-in-law, Rabbi Avraham Yoffen. It soon became the center of an entire movement.