ALL classical palaeographers are familiar with Persius' roster of writing materials: Now we take the book to hand, and the two-coloured parchment purged of hair, and papyrus, and a knotty reed. Of the items mentioned, only ‘two-coloured parchment’ presents any difficulty.I hope in this article to present at least a possible solution to this problem. An obvious supposition would be that Persius is merely referring to the natural differences in colour between the two sides of a piece of parchment.