Sequence

   Latin chant sung regularly after the Alleluia of the mass from the ninth to 16th centuries. Liturgical reforms resulting from the Council of Trent (1545–1563) eliminated from the Roman Catholic rite more than 4,500 known works. These four sequences remained: {}Victimae paschali laudes for Easter, Veni Sancte Spiritus for Pentecost, Lauda Sion for Corpus Christi, and Dies irae for Requiem masses. One other, Stabat mater dolorosa, was restored in 1727. The earliest notated sources of sequences date from the 10th century and the origin of the genre is controverted. One monk, Notker Balbulus (c. 840–912), describes adding new Latin text to long melismas of Alleluias as an aide-memoire. Few sequences in the earliest sources, however, refer explicitly to Alleluia chants, and so scholars believe that sequences developed as a para-liturgical genre along with Gregorian chant, composers providing completely new words and music in most cases.

   Sequences of the 11th and 12th centuries set poetic texts, often rhymed, as opposed to the prosae of the earliest examples. Many sequences follow a parallel construction in which the first and last musical phrases are heard once each, while all of the interior phrases are repeated: a bb cc dd . . . yy z. The majority of sequences, however, do not follow such strict parallelism.

   See also Adam of St. Victor.