The principal source for this edition of Isaac's Choralis Constantinus, vol. II, is the print issued in Nuremberg in 1555.
The original sources of the music—'s autograph and the fair copy that he provided to the Constance cathedral in 1509— lost. All surviving sources date from the 1530s and later. The patterns of transmission of music in sixteenth-century Germany are complex. Most prints and manuscripts contain a variety of pieces drawn from multiple sources. Nevertheless, by taking account of the known dates and provenance of sources, connections among people and institutions, and patterns of variants, it is possible to reconstruct the broad outlines of the transmission of the Choralis Constantinus II repertoire with reasonable confidence.
Mucb information about the transmission of this repertoire is found in Manfred Schuler, "Zur Überlieferung des Choralis Constantinus von Heinrich Isaac," Archiv für Musikwissenschaft 36 (1979): 68-76 and 146-54. Documentation of the information below is based on that source and studies of patterns of variants by the current editors.
The earliest evidence of a plan to publish the collection is found in the preface to a 1537 print, in which the Nuremberg publisher Johannes Ott announced a forthcoming publication entitled Chorais cantus constantiensis. A musical example from the repertoire appeared in a theoretical treatise by Sebald Heyden, who was also working in Nuremberg, in the same year. Ott apparently had a complete manuscript exemplar, which is no longer extant, for volume II not long after that date. The source of his exemplar was probably Isaac's autograph. That manuscript was purchased in 1554 by the Augsburg book dealer Georg Willer, who financed the publication. Ott may have obtained it from the estate of Isaac's widow, who died in 1534. Ott died in 1546, and the work was finally published by his former printer Hieronymus Formschneider in 1555.
The surviving sources of the repertoire published as Choralis Constantinus II may be divided into two principal families: the "Nuremberg line" (sources deriving from the materials assembled by Ott for the print) and the "Constance line" (soures deriving from copies made from the Constance fair copy). A third family, which we may call the "Munich line," consists of Munich-based sources that duplicate pieces from the Nuremberg line. A few manuscripts appear to have derived Choralis II pieces from more than one source. The examples that circulated in theoretical treatises derive from the Nuremberg line.
Three manuscripts were apparently copied from Ott's original source. They have a number of correct readings where all sources traceable to the exemplar that Ott prepared for the print share common errors:
Five extensive manuscripts are traceable to copies of Ott's print exemplar. That exemplar included a number of unusual mensuration and proportion signs that were evidently imposed on Isaac's notation by the music theorist Sebald Heyden. Heyden's interventions must have taken place in two stages, the first corresponding to his treatises of 1537 and 1540. One manuscript is based on a copy that reflects this stage of the notation:
H-Bn MS Bártfa 8 was the ultimate source for five other manuscripts:
These manuscripts are related as follows: The principal source for the group is H-Bn MS Bártfa 8. H-Bn MS Bártfa 24 was copied mostly, but not entirely, from H-Bn MS Bártfa 8, and H-Bn MS Bártfa 2 was in turn copied from it. H-Bn MS Bártfa 20 and H-Bn MS Bártfa Pr1 were copied from H-Bn MS Bártfa 8. The source of H-Bn MS Bártfa Pr17 cannot be determined.
Three extensive manuscripts of the 1570s are traceable to a later stage of Ott's print exemplar. They include a few more complex (and anachronistic) mensuration and proportion signs than H-Bn MS Bártfa 8. All of them are derived from the same copy of the exemplar, which is likely to have been in Augsburg before the appearance of the print:
Another extensive manuscript of unknown date was based on a different copy of Ott's print exemplar:
A nearly complete copy of the collection, which must have been based on Ott's exemplar, is known through a surviving inventory to have been present in Heidelberg by the early 1540s.
A print containing two verses from Choralis II that appeared in Nuremberg in 1549 must also have been based on Ott's exemplar:
The following manuscripts, which contain only a few Choralis II pieces interspersed with other repertoire, probably derived their Choralis pieces from the Formschneider print:
The pre-1555 sources from the Constance line include two prints and three manuscripts that were apparently transmitted from copies of the Constance fair copy, possibly by Sixt Dietrich. They are:
RISM 15455 was in turn the source of pieces in the following manuscripts:
Three manuscripts include one or more pieces copied from RISM 15455 along with Choralis II pieces based directly or indirectly on on the printer's exemplar. They are:
Three manuscripts originating in Munich contain one piece that is found in both the first and the second volume of the Choralis print. Two other pieces in found in both Choralis I and Choralis II must have been included in Munich sources that are now lost. These pieces may have originated as part of either repertoire and then been reused in the other. Liturgical and stylistic considerations suggest that they belonged originally to the Choralis II set. The sources are:
D-Mbs Mus. MS 39 is the earliest member of this group. D-Mbs Mus. MS 33 was copied from D-Mbs Mus. MS 39, and D-Mbs Mus. MS 26 was in turn copied from D-Mbs Mus. MS 33. Choralis Constantinus I had a common source with, but was not copied directly from, D-Mbs Mus. MS 39.
Choralis II was also the source of musical examples in the following music theory treatises:
- Sebald Heyden, Musicae, id est Artis canendl libri duo
- Sebald Heyden, De arte canendi
- Heinrich Glarean, Dodecachordon
- Anonymous, Explicatio compendiosa doctrinae de signis musicalibus (D-B MS Mus. Theor. 1175)
- Scottish Anonymous, The art of music
- Ambrosius Wilphlingseder, Erotemata musicae practicae
- Lodovico Zacconi, Prattica di musica
The examples in Glarean, the anonymous Explicatio, and the Scottish Anonymous are based on Heyden's Musicae.
These relationships may be visualized in a stemma. Sources in brackets are not extant. Extant manuscript sources are abbreviated with the first three letters of the city and the number of the shelf mark where they are located. The Regensburg Thurn und Taxis library has the letters "TT" after the abbreviation of the city. Underlined sources appear in two places, since different pieces in them came through different lines of transmission. Intermediate sources are possible in every case and highly probable in the case of most sources that contain small numbers of Choralis II pieces.