Jacobus Sinapius. Rudolph II had ennobled him in 1607, had appointed him his Imperial Distiller, and had made him curator of his botanical gardens as well as one of his personal physicians. Voynich (and many other people after him) concluded that Jacobus owned the Voynich manuscript prior to Baresch, and he drew a link from that to Rudolf's court, in confirmation of Mnishovsky's story. Jacobus's name has faded further since Voynich saw it, but is still legible under ultraviolet light. It does not match the copy of his signature in a document located by Jan Hurych in 2003. As a result, it has been suggested that the signature was added later, possibly even fraudulently by Voynich himself. Baresch's letter bears some resemblance to a hoax that orientalist once played on Athanasius Kircher. Müller sent some unintelligible text to Kircher with a note explaining that it had come from Egypt, and asking him for a translation. Kircher reportedly solved it. It has been speculated that these were both cryptographic tricks played on Kircher to make him look foolish. Raphael Mnishovsky, the friend of Marci who was the reputed source of the Bacon story, was himself a cryptographer and apparently invented a cipher which he claimed was uncrackable (c. 1618). This has led to the speculation that Mnishovsky might have produced the Voynich manuscript as a practical demonstration of his cipher and made Baresch his unwitting test subject. Indeed, the disclaimer in the Voynich manuscript cover letter could mean that Marci suspected some kind of deception. In his 2006 book, Nick Pelling proposed that the Voynich manuscript was written by 15th-century North Italian architect Antonio Averlino (also known as "Filarete"), a theory broadly consistent with the radiocarbon dating. Language hypotheses Many hypotheses have been developed about the Voynich manuscript's "language", called Voynichese: Ciphers According to the "letter-based cipher" theory, the Voynich manuscript contains a meaningful text in some European language that was intentionally rendered obscure by mapping it to the Voynich manuscript "alphabet" through a cipher of some sort—an algorithm that operated on individual letters. This was the working hypothesis for most 20th-century deciphering attempts, including an informal team of NSA cryptographers led by William F. Friedman in the early 1950s. The counterargument is that almost all cipher systems consistent with that era fail to match what is seen in the Voynich manuscript. For example, simple substitution ciphers would be excluded because