Its original editor assigned the codex to the early third century, or around AD 200, on the basis of its style of handwriting.

[1] Herbert Hunger later claimed that the handwriting should be dated to an earlier period in the middle or early part of the second century.

But more recently James Royse argues that, with the possible exception of John 13:19, the corrections are all by the hand of the original copyist.

[7] Elizabeth Schrader Polczer adds that, in the case of John 11, the copyist may have introduced an entirely new character, Martha, to the text, but this argument remains controversial.

[11] In John 13:5 it has unique textual variant ποδονιπτηρα (podoniptēra, "foot-basin") instead of νιπτηρα (niptēra, "basin").

[12] The preservation level of 𝔓66 surprised scholars because the first 26 leaves were basically fully intact, and even the stitching of the binding remained.