I shall be talking about two manuscripts that illustrate the way in which watermarks can help in dating and authenticating undated and questionable manuscripts. The first, an undated verse letter by John Donne at the Bodleian library, is written on paper with the same watermark as a dated letter from Donne at the Folger. Along with certain other features common to them both, the watermark confirms the approximate date ascribed to it. The second manuscript is a letter from Benjamin Franklin, apparently to Captain Timothy Folger. On the surface the letter looks like a single, genuine letter, but when you examine its watermark you see two overlapping sets of chain lines, two watermarks and a few other anomalies. Though the writing is throughout in Franklin's hand, someone unknown concocted a letter to appeal to our founder.