The text of this composition appears from the late 15th century onward coupled with various monophonic melodies in sources of Flemish and Dutch provenance; Ike de Loos characterizes the chant as "a true Netherlandish antiphon, which was unknown outside the Low Countries."[1] Assigned no fixed liturgical place, the settings of this text appear in various types of manuscripts (processionals, antiphonals, secular songbooks, etc.), employed as a prayer for protection against the plague in processions, at the end of mass, or in private devotions and paraliturgical contexts.[2] The present polyphonic version seems not to draw on the melodic material of either of the main monophonic versions - only a possible echo of the first few notes in both sections of the Mode 1 melody offers any hint that the composer of the polyphony had one of these melodies in mind.[3]

On the possibility that this composition is the work of "Sampson," see the Editor's Commentary to Quam pulcra es.

Notes
[1] "een echte Nederlandse antifoon, die buiten de Lage Landen niet bekend was." Ike de Loos, 'Een overclaer vat: een Maria-antifoon uit de late Middeleeuwen', Tijdschrift voor Gregoriaans, 27 (2002): 2-8; republished online in Jubilate, May and September 2004.

[2] See the listing of sources by Ike de Loos in Chant Behind the Dikes.

[3] Both monophonic melodies are presented in De Loos, 'Een overclaer vat.' The section openings of the Mode 1 version, ACD ("Hec") and GAB-fa ("Sancta"), correspond loosely to mm. 1 and 57 of the LonBLR 11 E.xi composition.