Rabbi Yitzhak HaLevi Herzog הרב יצחק הלוי הרצוג

Łomża, where he was born in 5649, let him go as a boy: the family moved to Leeds and then Paris, and he studied both with his father and at university: the Sorbonne, London, an MA in Semitics, a doctorate in literature. He received semikhah in 5670. Such a combination—a full talmudist and a full university scholar—was rare, and in Lithuania it was regarded with suspicion.

Tekhelet. His doctorate was on what tekhelet was made from—the blue thread of the tzitzit, lost for fifteen hundred years. He went through the sources, the chemistry and the zoology and named his candidate among the snails. Later researchers corrected his conclusion, but the subject is still begun with him: he was the first to put the question scientifically.

Ireland. He was rabbi of Belfast and then Chief Rabbi of Ireland, until 5696. The Irish called him "the Sinn Féin rabbi": he learned Irish and did not hide his sympathy for their independence.

The Land of Israel. In 5696, after Rav Kook's death, he was chosen Ashkenazi Chief Rabbi; from 5708 Chief Rabbi of the State of Israel. On him lay questions nobody before him had faced: how Jewish law is to live alongside state law; what to do about the agunot the war had left by the tens of thousands; what a court ordered by the Torah looks like in a country with a parliament. He wrote a book about it, Tehukah le-Yisrael al pi ha-Torah—"A Constitution for Israel according to the Torah".

The children. The chief work of his life is held to be not his books. After the war thousands of Jewish children had been placed in monasteries, orphanages and peasant families—and many did not know who they were. Herzog travelled Europe, obtained audiences with governments and with the Vatican, demanded lists and took children back. How many exactly he brought out is disputed; that he travelled and demanded is documented.

His responsa appeared as Heichal Yitzchak. In 5718 he received the Israel Prize for rabbinic literature. His son Chaim became the sixth president of Israel.