Watching a recent Martin Clunes show on TV, called, I think, the Islands of Britain, he met the self-styled head of the island of Forvik, an also self-styled 'Crown Dependency.
The fellow claims to have researched the legal status of the Shetland Islands and cannot find any dated link to the English or Scotish governments. He said on camera "If there's no date, then it didn't happen".
Which underlines the significance of dates in the Genesis account (whatever you, dear reader, think of them). Conversely to Forvik: if there is a date, it did happen!
Genesis makes the point that its events happened in history, and so they can be dated; and are.