Recently rediscovered choirbook. Contents: 9 mass ordinary cycles, 20 cycles of mass propers (each consisting of an introit, alleluia and sequence), 2 independent Proper compositions, and a Regina caeli laetare;

The 'core' fascicle - gatherings IX-XXI - contains Mass Propers mixing 'de tempore' and 'de sanctis' from Lent to the Purification of the Virgin, and was copied by a single scribe. The Propers bear neither title nor composer attribution, but a comparison with the second part of the Choralis Constantinus reveals that most of them are by Heinrich Isaac. Other fascicles were added subsequently; the repertory contains some vernacular song interpolations in German. Modern pencil foliation.

210 paper folios. The manuscript's core is a fascicle constituting gatherings IX-XXI. All its gatherings are quinternions, with the exception of IX and XI, which are sexternions. Gathering I is a bifolio in which the first recto folio is pasted to the pastedown. The 'toni communes missae' for four voices are notated in this front opening.

There are three other fascicles: (1) Gathering II (quaternion); (2) Gathering III (sexternion) (3) Gatherings IV-VIII (gathering IV: nonion)

At the very end of the manuscript one gathering may be missing, where staves for an incomplete composition could have continued.

The original wooden boards measure 42.5 x28 cm, and dark-brown leather with blind and floral stamps is used as a cover, with the board badly damaged by worms. It bears four brass corner pieces and a central boss; the original leather straps have been torn off. The rounded spine bears two paper labels, the older one marked with the number '5' (probably added either in 1780 or later, according to Habrichs catalogue) and the other marked with the number '14' (c.1911).

originally in parish library of St. Jakub (St. James Major), Prague. Since 1931, on deposit at Brno City Archive

Gathering II, an encircled anchor with a star, 7 x 4 cm. Gathering III, small eagle as below. Gatherings IV-VIII, the above-mentioned encircled anchor, a coat of arms with a diagonal bar and two six-pointed stars, a grape cluster with the stem and base of a chalice, and crossed arrows with a star. Gatherings IX-XXI, a small eagle with an eye and crown (5.5 x 5 cm).

None of the watermarks has an identical match in the catalogues of Briquet and Piccard. The fact that similar watermarks do occur elsewhere in Central Europe, mostly in the south German and Austrian lands as well as in Venice, supports a date of origin around the middle of the 16th century.

Modern pencil foliation