Each weekly Torah portion adopts its name from one of the first unique word or words in the Hebrew text. Dating back to the time of the Babylonian captivity (6th Century BCE), public Torah reading mostly followed an annual cycle beginning and ending on the Jewish holiday of Simchat Torah, with the Torah divided into 54 weekly portions to correspond to the lunisolar Hebrew calendar, which contains up to 55 weeks, the exact number varying between leap years and regular years.