A suffix (.1, .2, .3, etc.) can be applied to a Cantus ID number within the Cantus Index catalogue in the case of a similar text of the same genre with a significant variant.

Note: For the networked manuscript databases, the policy remains to enter all words as found in the individual manuscripts, regardless of small differences that might exist between the manuscript and the Cantus Index catalogue record.

Decisions regarding what constitutes a variant are made first by researchers entering new chant texts; these entries are subject to review by senior editors and website managers in order to normalize records, and maintain consistency and integrity among the data.

Following are some guidelines for indexers:
Use the unaltered, original Cantus ID number for texts that:
  • differ only in case ending or verb tense;
  • differ in only a few words (1-3), where the meaning of the text is generally the same;
  • end with the word “Alleluia” (or repetitions of it).
Create a new record with a “variant” to demonstrate a different but related text when:
  • there is an entirely different phrase (4+ words) added either in the middle or at the end;
  • the text begins with a few different words but continues in a similar or identical manner with no or very little difference in meaning;
  • if the text begins with "Alleluia" but is otherwise identical (this policy is owing to the legacy numbering of this decades-old project).
Also, note that major and minor versions of similar chant texts receive the same base number with “variant” endings (.1., .2, etc.) in order to keep the connection between these chant texts while allowing the system to differentiate them with unique Cantus ID numbers.
  • The full-text search will find the chant even if a couple of the words are different.
  • Users searching from the Cantus Index hub for chants across multiple, networked databases will benefit from having more plentiful results; that is, our identification and grouping of similar chants containing minor variants under single Cantus ID numbers will improve search results.
  • Study the application of footnoted variants by René-Jean Hesbert in Corpus Antiphonalium Officii. Note that identical texts that had different melodies in the sources he studied were assigned different CAO numbers; such a procedure will need to be decided upon in the future in the case of Cantus Index, where, at this point, identical texts are kept under the same number regardless of melody (since not all melodies have been recorded in full in all manuscript sources).