Yitzhak HaLevi Herzog (; 3 December 1888 – 25 July 1959), also known as Isaac Herzog or Hertzog, was the first Chief Rabbi of Ireland, his term lasted from 1921 to 1936. From 1936 until his death in 1959, he was Ashkenazi Chief Rabbi of the British Mandate of Palestine and of Israel after its independence in 1948. He was the father of Chaim Herzog and grandfather of Isaac Herzog, both presidents of Israel. Biography Isaac Halevi Herzog was born at Łomża in Russian Poland, the son of Liba Miriam (Cyrowicz) and Joel Leib Herzog. He moved to the United Kingdom with his family in 1898, where they settled in Leeds. His initial schooling was largely at the instruction of his father who was a rabbi in Leeds and then later in Paris. After mastering Talmudic studies at a young age, Yitzhak went on to attend the Sorbonne and then later the University of London, where he received his doctorate. His thesis, which made him famous in the Jewish world, concerned his claim of re-discovering Tekhelet, the type of blue dye once used for the making of Tzitzit. Rabbi Herzog's descendants have continued to be active in Israel's political life. His son Chaim Herzog was a general in the Israel Defense Forces and later became ambassador of Israel to the UN and sixth President of Israel. His son Yaakov Herzog served as Israel's ambassador to Canada and later as Director General of the Prime Minister's Office. He also accepted an offer to become Chief Rabbi of the British Commonwealth but due to ill health never took up that role. His grandson Isaac Herzog is the President of Israel. He also previously served as a member of the Knesset, Israel's parliament, and head of the opposition. He previously served as housing and tourism minister and minister of welfare and later was chairman of the Jewish Agency. Rabbinic career Rabbi Herzog served as rabbi of Belfast from 1916 to 1919 and was appointed rabbi of Dublin in 1919. A fluent speaker of the Irish language, he supported the First Dáil and the Irish republican cause during the Irish War of Independence, and became known as "the Sinn Féin Rabbi". He went on to serve as Chief Rabbi of Ireland between 1922 and 1936, when he immigrated to Palestine to succeed Rabbi Abraham Isaac Kook as Ashkenazi Chief Rabbi upon his death. He