Julius Caesar did NOT standardize the week. Its first recorded use in Rome was during the reign of Augustus. Romans then used the seven day week alongside the eight day nundinae until the fourth century when the latter was outlawed by Christians when they attained power. The Jews invented the week during their exile in Babylonia beginning in 586 BCE, basing it on a Babylonian practice of regarding days 7, 14, 21, and 19 (49 counted from the first day of the previous month) of every month unlucky.. Thus the Babylonians themselves did not use an unbroken sequence of weeks. Furthermore, we have no prrof that its sequence was unbroken even by the Jews until the Roman inscription mentioned in Days of the week#Origins and discussed more fully in Days of the week#Astrological interpretations. —     