1. Joel ben Samuel Sirkis known as the Bach, was a prominent Ashkenazi posek and halakhist, who lived in Central Europe and held rabbinical positions in Belz, Brest-Litovsk and Krakow, and is considered to be one of the greatest Talmudic scholars of Poland.
Joel Sirkis is known for his liberal rulings in his responsum in which he challenges the rabbinic status quo.
Joel Sirkis later occupied the rabbinates of Lukow, Lublin, Medzyboz, Belz, Szydlowka, and Brest-Litovsk, finally settling in Krakow in 1619, where he married Bella, the daughter of Abraham of Lwow and was appointed Av Bet Din of Krakow and head of the yeshivah.
Joel Sirkis's work received the approval of the greatest rabbinic scholars of his time, even those outside of Poland.
Joel Sirkis was critical of those who relied solely on the Shulchan Aruch for halachic decisions, rather than on the Talmud and the Geonim.
Joel Sirkis extended the permission to sell leavened food to a non-Jew before Passover to include the sale of the room in which such food was found.
Joel Sirkis permitted the reading of secular, non-Hebrew books on the Sabbath and liberalized certain laws to allow for the greater enjoyment of the festivals.
Joel Sirkis allowed Jewish physicians to violate the Sabbath when treating non-Jewish patients.
Joel Sirkis permitted church melodies in the synagogue if they were universal in appeal.
Joel Sirkis excused people sensitive to colds or those lacking warm clothing from the obligation to dwell in booths during Sukkot and permitted women to dress in men's clothing during extreme weather conditions when this type of attire was more comfortable.
Joel Sirkis's son-in-law was David HaLevi Segal, and among the Bach's descendants is the prominent Ukrainian rabbi Betzalel HaLevi of Zhovkva, who was the maternal grandfather of the Hasidic master, Simcha Bunim of Peshischa.