The term week came from the Saxon word "wikon," signifying 'a turn, or a succession of, as in days.' The Babylonians had long used the seven-day week, and it may be from Babylon the Hebrews adopted it after their captivity in the sixth century B.C. The Bible's Book of Genesis tells of the creation of the world by God in six days, after which God rested on the seventh. The seventh day became the Jewish day of rest, the Sabbath. In early Rome, however, the civil week consisted of eight days, until Emperor Constantine decreed in 321 A.D. that the civil week would now be comprised of seven days.