Conditor alme siderum

Conditor alme siderum. Latin, author unknown. This hymn, of unknown authorship but in Ambrosian form, exists in many different versions (see JJ, p. 257). It came into the liturgy as an Advent Vespers hymn in the 9th-century New Hymnal (see Medieval hymns and hymnals*). Its precise assignment varied, and sometimes a hymn will be signalled early in a liturgical season, with the implicit expectation that it will be used throughout the season. A non-exhaustive survey (see Cantus database*) shows its use for:  general use in Advent: Aachen (Aix-la-Chapelle), Domarchiv, G 20 (13th century, Aachen); Worcester cAthedral MS F 160 (Worcester Cathedral, ca 1230); Vespers on all Advent Sundays,...