For reasons I can only guess at, there has come to be a habit of saying not that the manuscript’s parchment was made before 1440 (which is true, as far as the scientific data is concerned), but instead adding nearly another 30% to the indicated date-range.
So (especially among those still hoping it will prove a manuscript made by one Christian faction rather than another), there are increasing numbers of bloggers adopting a vague – and never quite-explained – assertion that the manuscript dates from “the 1450s”.
Well, it doesn’t.
There is no evidence at all, and certainly nothing reliable, adduced in support.
I reckon the answer lies somewhere in the wiki list of “important events” for 1450+
But whatever the obscure reason might be, the fact is that “1450s” just … ain’t … so.
Perhaps the parchment was inscribed later than 1438.. but we don’t know that; there’s no evidence to support the contention.
1404-1438. That’s it.
– unless, or until, another formal (and equally independent) scientific evaluation is published.