Trattato della pittura : manuscript, fair copy, produced in the workshop of Cassiano dal Pozzo.

Clean copy of the manuscript made in the atelier of Cassiano dal Pozzo, secretary to Cardinal Francesco Barberini, the nephew of Pope Urban VIII.
"Dal Pozzo owned a copy of Leonardo's writings when he arrived in Rome from Florence in 1612 (unpublished research of Pauline Maguire). Around 1634, Dal Pozzo gave this copy (modern designation vb), now in the Biblioteca Apostolica Vaticana, to Cardinal Barberini for the Barberini Library. It bears the collocation Barb. Lat. 4304. Early in the publication project, Dal Pozzo compiled m3 (Biblioteca Ambrosiana MS H228 inf.), a text derived from a different source than vb's. He commissioned original drawings from Nicolas Poussin (1594-1665) and original diagrams from the scientific researcher and mathematician, Gaspare Berti (1601-1643), to be used for engravings in a lavish publication. Both vb and m3 were used to compile the manuscript offered for sale."--Sotheby's (Janis Bell and Pauline Maguire Robinson).
Part 1 (fols.1r-101r) is a copy of the text and sketches of Dal Pozzo's manuscript vb (BAV MS Barb. Lat. 4304). The corrections and supplemental text inserted in the margins and between lines of text derive from m3. Sparti (2003) incorrectly surmised that the annotations were by Trichet du Fresne, an attribution that cannot be sustained by handwriting comparisons nor by what we can firmly ascertain about the early date of this text. The copy from vb was probably executed before Dal Pozzo employed Poussin and Berti to illustrate the text of m3, which took place in 1633-1634. Dal Pozzo updated the manuscript with additions and corrections years before Trichet du Fresne became involved in the Trattato publication project. Thus, this copy was an important point of reference during the years in which Leonardo's Trattato took final form in Rome.
Part 2 (fols. 102-115v) is a copy of the first compilation of excerpts (the so-called "added chapters") that Dal Pozzo received, the original of which is bound in m2. The corresponding images (fols. 116-125) are missing from the source manuscript (m2) but are found in two other copies, m4 (BAMi MS H229 inf.) and n1, the elegant copy in Naples known as the Codex Corazza.
Part 3 (fols. 126r-132r) is a copy of Mazenta's memoir, the original of which is bound in m2 (Biblioteca Ambrosiana MS H 227 inf.).
Part 4 (fols. 132r-133r) is a copy of the "checklist" of chapter headings from Dal Pozzo's m3.
Part 5 (fols. 134-162) contains pen and wash copies of fifty-three diagrams and figures prepared for m3. The size of the figure drawings conforms to Nicolas Poussin's originals and were most likely made by tracing or lucidare, as were other copies in the Poussin atelier.