Rabbi Isaiah Horovitz (Hebrew: ישעיה הלוי הורוויץ), (c. 1565 – March 24, 1630), also known as the Shelah ha-Kadosh (the holy Shelah) after the title of his best-known work, the Shnei Luḥot HaBrit. He was a prominent Levite rabbi and mystic. Isaiah Horovitz was born in Prague around 1565. His first teacher was his father, Avraham ben Shabtai Sheftel Horowitz, a notable scholar and author, and a disciple of Moses Isserles (Rema). Horowitz studied under Meir Lublin and Joshua Falk. He married Chaya, daughter of Abraham Moul, of Vienna, and was a wealthy and active philanthropist, supporting Torah study, especially in Jerusalem. In 1590, in Lublin, he participated in a meeting of the Council of Four Countries, and his signature is on a decree that condemns the purchase of rabbinic positions. In 1602, he was appointed head of Beis Din in Austria, and in 1606 was appointed Rabbi of Frankfurt am Main. In 1614, after serving as rabbi in prominent cities in Europe, he left Frankfurt—following the Fettmilch uprising—and assumed the prestigious position of chief rabbi of Prague. In 1621, after the death of his wife, he moved to Palestine, was appointed rabbi of the Ashkenazic community in Jerusalem, and married Chava, daughter of R. Eleazer. In 1625, he was kidnapped and imprisoned, together with 15 other Jewish rabbis and scholars, by the Pasha (Ibn Faruh) and held for ransom. After 1626, Horowitz moved to Safed, erstwhile home of Kabbalah, and later died in Tiberias on March 24, 1630 (Nissan 11, 5390 on the Hebrew calendar). In his many Kabbalistic, homiletic and halachic works, he stressed the joy in every action, and how one should convert the evil inclination into good, two concepts that influenced Jewish thought through to the eighteenth-century, and greatly influenced the development of the Ḥassidic movement. (via Wikipedia)