- Cortona, 14th century (1368); parchment; mm 290 × 200; ff. VI, 63, II’; 17 coloured astronomical drawings (ff. 48r-51v, 53r, 54r-v).
- San Daniele del Friuli, Biblioteca Civica Guarneriana, 238.
The book, which belonged to Giusto Fontanini and was by the latter left to the Biblioteca Guarneriana, contains a fourteenth-century vernacular translation of the Tresor first book (ff. 1r-62v) and astronomical computations (ff. 62v-63v).
Although Brunetto Latini had conceived his Tresor as a pyramidal work, through which starting from the notions on different disciplines accumulated in the first book readers could only step-by-step reach the ‘pure gold’ of knowledge, that is to say the Rettorica of the third book, nevertheless less refined audience let above all the first book become a best-seller. Excerpted form its narrative macrostructure, it had a separate, autonomous circulation like gatherings of an encyclopaedia, though etched by contamination, rearrangement and interpolation due to the copyists hands. The Guarnerianus codex (known by the initial S) is a witness of such Italian success, particularly in its Tuscan reception, a full-page written book that is made precious by a dense series of coloured diagrams as a text endowment on the astronomy-dedicated sheets. The dated codex shows the copyist’s subscription at the end (f. 63r) «Explicit liber Thesaurii. Deo gratias, amen. Qui scripsscit [sic] scribat, semper cum Domino vivat. | Vivat in celis Vannes Benedicti in nomine felix. | Completo libro referamus gratiam Christo. Amen, amen, amen. Cortone, millesimo tricentessimo LXVIII, indictione VIa, tempore domini Urbani pape quinti». In the initial flyleaves there is the ownership notice by the bibliophile Giusto Fontanini (1666-1736) dated 1730. There follow notes of a collation with other Tresor manuscripts that were drawn out in Rome, September 20th, 1723.