Yahrtzeit of Rav Hai Gaon (969-1038), the last of the Babylonian Talmudic sages called the "Geonim." Rav Hai Gaon authored a commentary on the Talmud as well as a collection of responsa. He was the head of the yeshiva at Pumbedita, Babylonia, having succeeded his father, Rav Sherira Gaon. The death of Rav Hai Gaon marked the end of Babylon's 800-year reign as the center of Jewish life; the focus was then split between North Africa and Europe, giving rise to the customs of Sephardi and Ashkenazi Jewry.