The meaning of the earth being divided is usually taken to refer to a patriarchal division of the world, or possibly just the eastern hemisphere, into allotted portions among the three sons of Noah for future occupation, as specifically described in the Book of Jubilees, Biblical Antiquities of Philo, Kitab al-Magall, Flavius Josephus, and numerous other antiquarian and mediaeval sources, even as late as Archbishop Ussher, in his Annals of the World.
Flavius Josephus
Archbishop Ussher