Pactum foederis Urbani Grandieri
On August 18, 1634, after having been convicted of practicing witchcraft, the Roman Catholic priest Urbain Grandier was burned at the stake. During his trial, this "diabolical pact," written in reversed Latin, was introduced as evidence of his crimes. It contains several sigils and scribal abbreviations and was purportedly signed by a council of demons and the Devil himself.
In his nonfiction book based on the "Loudun Posessions," Aldous Huxley suggests many involved in the trial, including learned Jesuits and Franciscans, questioned the education level and linguistic acumen of these princes of darkness (The Devils of Loudun. Harper & Brothers, 1952. 181-82), but no one, I think, can question their asemic acuity or their potential as graffiti/tattoo writers.