SEQUENCES. — Initially, the sequence was nothing more than a vocalization on the final syllable of the Alleluia of the Gradual; it was the *jubilus* or *jubilatio*, which was divided into sequences for the breath of pauses or for the alternation of choirs. Later, a text adaptable to the melody was substituted, and both the text and its melody were called a sequence.
The influence of the Byzantine musical form of the *koikon* upon this development remains uncertain. Notker Balbulus (d. 912), a monk of St Gall, is regarded as the father of the sequence; though some trace its origins back to the 8th century in France. A fugitive monk from the monastery of Jumièges near Rouen, destroyed by the Normans (c. 862), had brought to St Gall an antiphonary containing some sequence texts. Notker did not like these, but they moved him to compose others in their style and manner. The first fruits of this new composition are found in these two pieces: *Laudes Deo concinant orbis universus, qui gratis est redemptus* and *Coluber Adae deceptor*. Notker did not only use the melody of the final syllable of the Alleluia, but also those of the two preceding syllables, *le* and *lu*, to insert the text. At first, the sequence was not adorned with homophony. But in the interval from the end of the 10th to the beginning of the 12th century, it appears with frequent assonances and rhymes, and is very free in its rhythm, as, for example, *Victimae paschali* of Wipo. Then it acquires a rhythmic regularity, which may be polyrhythmic and, generally choosing a trochaic movement, it clothes itself in rhymes and ends by distinguishing itself from the hymn, which is mostly iambic, only by its own solemnity proper to the grave trochee and by the melodic multiplicity of its strophes: an example is the *Veni Sancte Spiritus*, the golden sequence, whose authorship is now more attributed to Stephen Langton (d. 1228) than to Pope Innocent III. Sequences are distinguished by names often of obscure significance: they are taken from the beginning of the alleluiatic verse, as *Dies sanctificatus* of Christmas; from names of instruments: *organa*, *sediculae*, *symphonia*; others seem to be names derived or translated from Greek: *Graeca*, *hypodiaconissa*, *Hieronyma*; from indications of popular melodies used: *puella turbata*, *planctus pueri capti*, *planctus cigni*, etc. The greatest writer of sequences was Adam of St Victor (v.).
In early times the texts of the sequences and their respective melodies were limited to single regions. Several periods with local production are distinguished: the German (St Gall), that of northern Italy (Verona, Nonantola), French (Limoges), English (Winchester). By the age of rhymed sequences some became of general or almost universal use in the Western Church: thus for Christmas *Natus ante saecula*; for Pentecost *Sancti Spiritus adsit*; for the feast of the Apostles *Clare sanctorum*; for St John the Baptist *Sancti Baptistae*. France and Germany were the most fertile homelands of the sequences. There were also secular, even satirical, sequences, as is proved by the *Carmina Burana* and the *Carmina Cantabrigiensia*. The Middle Ages had a predilection for this kind of poem, in which it expressed its genius and its deep and typical emotions. More than 5,000 sequences have been left to us by II. Before the uniform reform of the Missal carried out by Pius V (1570), the liturgical year contained 150 of them. At present only five remain: *Victimae paschali*, *Veni Sancte Spiritus*, *Lauda Sion Salvatorem*, *Stabat Mater*, *Dies irae*. This marks a final typical evolution: born from the Alleluia of the Mass, it appears in a Mass without Alleluia.
SEQUENCES IN HEBREW LITURGY. — *Sequentia* is the translation of ἀξιόλογωσις, which in Byzantine liturgical language signifies a complex of ceremonies and prayers that accompany and follow a rite (e.g., Baptism, Matrimony, the washing of feet), and the rules concerning a free poetic-musical composition. Affined to it in Hebrew liturgical terminology is *qarôbh* “to approach, to offer”; the *hazzān* (religious officiant, cantor) performs the *qrb*, i.e., intones a liturgical hymn which is a free development of the ideas contained in the traditional liturgical text that precedes II. The historical development of the term seems to be marked by three stages: *qerôbhân*, ἀξιόλογωσις, *sequentia*.