Victor in Paris. These sequences, patterned after the Greek model, approached more and more the form of the hymn, in which they finally disappeared. In the sequences the vernacular, as well as Latin, was employed and they were freely used in the Mass, becoming ‘a sort of people’s song.’ But since they were in reality extra-liturgical, they were all suppressed, except five, when the Council of Trent revised the Roman liturgy in the sixteenth century. The five at present in use are: _Victimæ Paschali_, appointed for Easter Sunday, written by Wipo early in the eleventh century, the oldest of the five and the only one similar in structure to Notker’s sequences; _Veni Sancte Spiritus_ for Whitsunday, written probably by Innocent III at the end of the twelfth century, called ‘the Golden Sequence’ by mediæval writers; _Lauda Sion_ for the festival Corpus Christi, written by St. Thomas Aquinas supposedly about the year 1261; _Stabat Mater_, sung since 1727 on the Friday in Passion Week, of uncertain authorship; and _Dies Irae_, sung on All Souls’ Day and in the Requiem or Mass for the Dead, written by Thomas of Celano late in the twelfth century or early in the thirteenth century. In the thirteenth century the poetry of the Latin Church attained its period of greatest brilliance and amid the rich efflorescence of this wonderful epoch the _Dies Irae_ stands incomparable, the finest example of rhymed Latin poetry of the Middle Ages. Second to it in poetic beauty is the _Stabat Mater_. It should be added that the authors of the above sequences were combined poets and composers, as poetry and music were twin-born arts during the Middle Ages. Another of the many illustrations of the readiness with which the churches of the West accepted the musical practices of the East was the ‘trope,’ which was adopted among the Franks in the ninth and tenth centuries from the many Byzantine musicians who came into the West during this period. The trope was not unlike the sequence in its development. The name was originally given to any succession of tones without text that occurred in the florid chants. Tuotilo of St. Gall (died 915) developed the tropes into quasi-independent compositions by setting words to them and interpolating them among the chants of the Mass, thus thrusting them into the Gregorian liturgy. These interpolations, some very extensive and ornate, found their way into all the Mass-chants except the Credo, which was considered too sacred to violate. But since the tropes were regarded by the Council of Trent as weakening accretions to the venerable structure of church-music, they, as well as the sequences, were banished from the liturgy in its final revision. III