Based on the Wikipedia article linked in that comment, it refers to papyrus fragments specifically, the most recent one being from aprox. the IXth century. [1]

Based on the Wikipedia article linked in that comment, it refers to papyrus fragments specifically, the most recent one being from aprox. the IXth century. [1] More recent texts were copied into more durable materials: > By the beginning of the fourth century A.D., the most important books began to be manufactured in parchment, and works worth preserving were transferred from papyrus to parchment. [2] By the way, I don't know enough about history or archaeology to agree or disagree with the comment, I just looked up the sources because I was also confused by the phrasing. [1] https://en.wikipedia.org/wiki/List_of_New_Testament_papyri https://en.wikipedia.org/wiki/List_of_New_Testament_papyri [2] https://en.wikipedia.org/wiki/Papyrus#History https://en.wikipedia.org/wiki/Papyrus#History