R. Abraham Isaac Kook, first Ashkenazi chief rabbi of modern Erez Israel. Rav Kook was born in Griva, Latvia in 1865. His father was a student of the Volozhin Yeshiva, the center of mitnagdut, whereas his maternal grandfather was a member of the Hassidic movement. He entered the Volozhin Yeshiva in 1884, where he became close to the Rosh HaYeshiva, Rav Naftali Zvi Yehuda Berlin (the Netziv). Already in his youth, he was well known as a prodigy. At the age of 23, he entered his first rabbinical position. Between 1901 and 1904 he published three articles which anticipate the fullydeveloped philosophy which he developed in the Land of Israel. In 1904, he came to the Land of Israel to assume the rabbinical post in Jaffa, which also included responsibility for the new secular Zionist agricultural settlements nearby. His influence on people in different walks of life was already noticeable, as he attempted to introduce Torah and Halakha into the life of the city and the settlements. The outbreak of the First World War caught him in Europe, and he was forced to remain in London and Switzerland for the remainder of the war. While there, he was involved in the activities which led to the Balfour Declaration. Upon returning, he was appointed the Rav of Jerusalem, and soon after, as first Chief Rabbi of Israel (though the state had not yet been been born). Rav Kook was a man of Halakha in the strictest sense, while at the same time possessing an unusual openness to new ideas. This drew many religious and nonreligious people to him, but also led to widespread misunderstanding of his ideas. He wrote prolifically on both Halakha and Jewish Thought, and his books and personality continued to influence many even after his death in Jerusalem in 1935. His authority and influence continue to this day. R. Kook was a prolific writer, who, according to his students, wrote out of the constant urge to create. He never attempted to construct a comprehensive system, and his style mirrors the quality of his personal insights and mystical reflections.

R. Elijah David Rabinowitz (ADe-Re-T; 1842/43–1905), Ashkenazi chief rabbi of Jerusalem. R. Elijah David was born in Pikeln, Lithuania. His father R. Benjamin Rabinowitz, who was rabbi of Zamosc and later of Wilkomierz, was called "Benjamin the righteous" because of his great piety; it was said that he never slept the night through and never ate a meal before completing the study of a tractate. As R. Elijah David was a twin, his brother being R. Zevi Judah, the name Teomim ("twins") was added to the family surname. R. Elijah David was known from his youth as an unusual genius and in 1874 was chosen rabbi of the community of Ponevezh. In 1893 he was appointed rabbi of Mir which, though smaller than Ponevezh, was renowned for its large yeshivah. His decision to move to Mir started a controversy, and the leaders of Ponevezh sent "an open letter" to Mir asking that their rabbi be "freed," but the appeal was ignored. His period at Mir was regarded as the creative period of his life. There he published the most notable of his works, as well as articles which appeared in many periodicals - Ha Tevunah, Ha-Me'assef, Kevod ha-Levanon, Ha-Zofeh, Ha-Maggid, Keneset Hakhmei Yisrael, Ittur Soferim, Keneset ha-Gedolah, etc. In Mir he wrote no less than a hundred works, especially notes and glosses to the Talmud, Maimonides' Mishneh Torah, the Tur of R. Jacob b. Asher, the Shulhan Arukh, and responsa. His novellae and glosses on the Jerusalem Talmud entitled Tuv Yerushalayim appeared in the Romm-Vilna edition (1922) and those on the Tur Hoshen Mishpat entitled Et Devar ha-Mishpat in the El ha-Mekorot (1959) edition of the Turim. His extraordinary erudition is discernible in his novellae and notes, and his great knowledge of historical matters from his correspondence on these subjects.