Rav Yaakov Emden (Ya'avetz)

Rav Yaakov Emden (Ya'avetz) (1698–1776), a towering scholar and controversial figure, author of the Beit Yaakov siddur (prayerbook). He was the son of Rabbi Tzvi Ashkenazi (the Chacham Tzvi). Father and son shared strikingly similar careers and temperaments: both were renowned scholars, both were outspoken and combative, and both waged relentless campaigns against the Sabbatean heresy. Remarkably, the yahrzeits of both father and son fall on Rosh Chodesh Iyar.