Brent Nongbri, “How Old Are the Oldest Christian Manuscripts?” Biblical Archaeological Review, vol. 26 no. 3 (Summer 2020), 45.
So how old are the earliest Christian manuscripts?
The evidence we have and a proper understanding of the multiple dating techniques at our disposal reveal that there is a significant discrepancy between what we actually know and what many have claimed to be true about the earliest Christian manuscripts. The Dura-Europos Gospel harmony, copied some time before A.D. 256, is actually the earliest relatively
securable datable Christian manuscript.
The famous Ryland Library Gospel of John, a small papyrus fragment sometimes touted as the earliest Christian manuscript with a date of “about A.D. 125,” is actually dated only by its handwriting, which cannot be assigned to such a narrow range. The style of writing used in the Rylands papyrus in fact persisted into the third century. So, while the Rylands papyrus (and a few other fragmentary Christian papyri) might be older than the Dura parchment, we can’t know for sure without some further testing.
The moral of the story is that we need to be aware of the contingency of our knowledge and the limits of our methodologies – to be honest about what we don’t know – before we can move on to establish more reliable knowledge about the ages
of our earliest Christian manuscripts
and to even form conclusions about the creation
and transmission of the New Testament.