The Copiale cipher is an encrypted manuscript consisting of 75,000 handwritten characters filling 105 pages in a bound volume.

An international team consisting of Kevin Knight of the University of Southern California Information Sciences Institute and Viterbi School of Engineering, along with Beáta Megyesi and Christiane Schaefer of Uppsala University in Sweden, found the cipher to be an encrypted German text.

The manuscript is a homophonic cipher that uses a complex substitution code, including symbols and letters, for its text and spaces.

[2] Previously examined by scientists at the German Academy of Sciences at Berlin in the 1970s, the cipher was thought to date from between 1760 and 1780.

The manuscript portrays, among other things, an initiation ritual in which the candidate is asked to read a blank piece of paper and, on confessing inability to do so, is given eyeglasses and asked to try again, and then again after washing the eyes with a cloth, followed by an "operation" in which a single eyebrow hair is plucked.

The Oculists were a group of ophthalmologists led by Count Friedrich August von Veltheim, who died in April 1775.