Tzvi Ashkenazi
Tzvi Hirsch ben Yaakov Ashkenazi (1656, Habsburg Moravia – May 2, 1718, Lviv), known as the Chacham Tzvi after his responsa by the same title, served for some time as rabbi of Amsterdam. He was a resolute opponent of the followers of the false messiah, Sabbatai Zevi. He had a chequered career, owing to his independence of character. He visited many lands, including England, where he wielded much influence. His responsa are held in high esteem. He was the grandson of Ephraim ha-Kohen, author of "Sha'ar Efrayim," who in turn was the son-in-law of a grandchild of Elijah Ba'al Shem of Chelm.
Read more about Tzvi Ashkenazi: Early Life and Education, Germany, London, Praised By Contemporaries, Descendants, Jewish Encyclopedia Bibliography