A codex of music collected by the composer, Ghiselin Danckerts, while in employ of the Cappella Sistina. Bound in parchment (a re-used notarial deed), the cover marked "N: 12 / Chiesa Nuova" in a 19th-century hand.

One scribe (Danckerts) copied most of the music; two hymns in another hand inserted between 3rd & 4th quire. Most of contents probably copied 1540s-1550s (Ghiselin died in the 1560s). There is some evidence of composer's amendments & changes to the music after (or as) copying.

In the archives of the Chiesa Nuova (S. Maria in Vallicella) in the 19th century, possibly transferred there as late as the mid-18th century.

48 folios in 5 fascicles (1-8, 9-14, 15-22, 23-35, 36-47), containing 15 pieces, all anonymous except for one attributed to (in fact probably signed by) Danckerts. This was probably the original opening page of the manuscript, though with re-ordering of quires at binding is now an internal page.

Parchment notary deed of Neapolitan origin, dated 1403 (re-used) [Note: Danckerts lived in Naples before moving to Rome in 1538, and retained a benefice there.]

two-tailed mermaid enclosed in a circle (diameter 50mm), crowned by a six-pointed star - similar to Briquet 685, n.13899 attested in Naples (1524-8) and Rome (1526). A similar though smaller watermark is found in Capp Sist 652 (f.35), a notebook of papal singers' receipts compiled by Ghiselin Danckerts around 1556, but on a leaf presenting different content dated 1539..

staff height 12.5mm, inconsistent distance between staves

numbered in lower right corner from 1-47 (28 repeated). Folios 6v-7 & 13v are blank.