Hebrew name: חכם צבי
Years: 1656–1718
Primary city: Altona, Ukraine
Rabbi Tzvi Ashkenazi, known as the Chacham Tzvi, was a leading Ashkenazi posek of the early modern period whose career combined communal rabbinic leadership with Rosh Yeshiva roles in major European centers. A sharp opponent of Sabbateanism, he became identified above all with his responsa sefer Chacham Tzvi, which secured his standing as one of the central halachic authorities of his era. He also authored a commentary on Choshen Mishpat and other writings, parts of which have survived.