Sotheby's announced this weekend that one of the oldest existing examples of written pornography in the English language will be sold at auction next month, a play by John Wilmot, the 2nd Earl of Rochester "reputed to be a series of copulation, buggery, masturbation, fellatio and bestiality enactments" printed around 1720. Rumors that Jenna Jameson was bidding for movie rights were unconfirmed at press time.
"First Known Printed Pornography in English Language on Auction Block" (AVN)
Lot 54: "Sodom, or The Gentleman Instructed. A Comedy. Hague [London]: Printed in the Year 1000000 [c.1720-1730]" (sothebys.com)
Update Examples from the porny poetry of John Wilmot at Pornokrates and Nerve (via Daze Reader)