Wissenschaftliche Stadtbibliothek Mainz, Hs I 171 is a manuscript from the second half of the 15th century. The provenance is from the Carthusians of Mainz.
The text on ff. 21v-22r is identified as a "Vision de anno 1387." The title identifies it as a vision found in an old book: "Sequitur alia visio Reperta in uno antiquo libro."
The text is in fact the "Cedar of Lebanon" vision (see Robert Lerner's 1983 Powers of Prophecy for the definitive study).
The preceding text, the "Visio de anno 1454" on ff. 20r-21v, is the Revelatio I of Denis the Carthusian.
