In addition to the chasidic works for which the 19th-century Rabbi Tzadok HaKohen of Lublin is most famous, he composed many legal works, including some written as rebuttals on specific topics. One of these, Meshiv HaTa’anah, critiques a short work called Megillat Ta’anot, which discusses astronomical calculations and the Jewish calendar, including how to address conflicts between rabbinic tradition and modern science. It was published together with Rabbi Tzadok’s Sefer HaZichronot, a summary of Maimonides’ list of the 613 commandments.