The Voynich Manuscript

Radiocarbon tests in 2009 dated the vellum to 1404–1438, long after Roger Bacon's death; the first identifiable owner is Jacobus de Tepenec, whose name is on folio 1r.

René Zandbergen, voynich.nu, 'The Radio-Carbon Dating of the Voynich MS' and 'Known history of the manuscript'

An illustrated codex in an undeciphered script, held at Yale's Beinecke Library as MS 408.

Sources3 sources

Primary source

Johannes Marcus Marci, Letter to Athanasius Kircher, tr. in Zandbergen, voynich.nu, 1665The 17th-century Prague tradition that Rudolf II bought the book and that Roger Bacon wrote it.
He believed the author was Roger Bacon, the Englishman.

Scholarship

René Zandbergen, The Radio-Carbon Dating of the Voynich MS (voynich.nu), IntroductionUniversity of Arizona radiocarbon dating of the parchment in 2009, announced 8 December 2009.
this parchment dates to sometime between 1404 and 1438 with 95% probability
René Zandbergen, Voynich MS: Known history of the manuscript (voynich.nu), The Bohemian period after Rudolf IITepenec's ex libris on folio 1r is the earliest ownership evidence; Marci's letter reports the Rudolf II purchase for 600 ducats and the Roger Bacon attribution.
The first positively identified owner of the Voynich MS is Jacobus Horčický de Tepenec.