Izaak Cylkow was born in 1841 in a small town in Mazovia, in Bieżuń, as a son of a scholar and expert on the Talmud, Mojżesz Aron. He grew up in Kuchary near Płońsk, where his father was employed by Szlomo Załemen Markus Posner, a wealthy representative of Varsovian middle class, as a tutor of his sons and forests administrator. Izaak took up education in the Rabbinical School in Warsaw when his father became a teacher of the Talmud there. Then, for a year, he studied at the Medical-Surgical Academy in Warsaw. Having been granted a scholarship by the Association of Lomdei Torah (Hebrew for „Studying the Torah”), founded at the Warsaw progressive synagogue in Daniłowiczowska Street, he was able to study in Berlin and Halle; he was awarded a doctoral degree in philosophy and Semitic languages.
After his return to Warsaw, in 1865, he was given a post of a preacher at the so-called German Synagogue in Daniłowiczowska Street. After a few years, the community, now more „Polish” than „German”, had grown so much that the building was not enough anymore. It was decided to build a new synagogue, the Great Synagogue in Tłomackie, one of the most beautiful religious buildings in Warsaw, and most of all, a meeting place for progressive Jewish community.
On 26th September, 1878, just before Rosh Hashanah, the Great Synagogue in Tłomackie had its ceremonial opening. Izaak Cylkow made a speech to the gathered guests, including Governor-general of Warsaw Count Paul Kotzebue and the President of the City Sokrat Starynkiewicz.
„We repose our hope in God,” Cylkow was saying. „That never again will we be considered to be a separate community or as a separate people treated, but as eligible children of our country, citizens of one country. Religions do not exist in order to exasperate and cause excitement[...] but only to bring people together and stimulate to act unanimously to do common good.”
The rabbi spoke in Polish and, as the Russian authorities did not protest, it was considered to be an informal permission to preach in that language, which had been forbidden since the January Uprising.
Izaak Cylkow put his ideas into practice. He taught at a religious school at the synagogue. It is likely that at the time it was the only school where they taught in Polish. He was also interested in education matters.
He was the author of the first, made by a follower of Judaism translation of the Old Testament into the Polish language. While doing so, he stayed faithful to the Jewish tradition and a prayer book in Polish. His sermons were published.
Czesław Miłosz in the introduction to his translation of Psalms wrote about the work of his predecessor: It is a poetically beautiful translation, and as I could later learn, it is also very faithful and because of that even more useful, as Cylkow is trying to preserve the order of the words of the original.
Izaak Cylkow died on 1st December, 1908 in Warsaw. He was buried in a Jewish cemetery in Okopowa Street in tomb no. 33.
More information about Izaak Cylkow in the catalogue Rav, Rabbi, Rebbe.