The border on an old map was current to the people who could not cross it.

Lines on old maps look arbitrary from a distance, and they were entirely concrete to the people they contained. A border you cannot cross determines who you marry, what work you can take, which family you see again. The map is later described as outdated, as though it had been a proposal, when for a generation it was the actual shape of possible life.

Be careful about calling any boundary artificial while people are living inside it. The same holds for constraints in ordinary life that others describe as merely formal. Whether a line is real depends on whether it can be crossed.