however, the last remains of Paganism had so completely disappeared that the prohibition of Friday services was removed by Pope Gregory II, who ordained the celebration of the sacred rites on the Fridays of Lent. Now the Gregorian Antiphonary contains a mass for each Friday in Lent, while there is none in the Gelasian Missal of the seventh century. If the mass is not a later interpolation, then the Gregorian Antiphonary certainly could not have been compiled before the time of Gregory II. Many historical considerations lead Gevaert to credit the completion and final formulation of liturgical chant to the Hellenic popes of the seventh and eighth centuries. Following the end of the Gothic kingdom and with the dominance of the Byzantine emperors begins the second period of church music in the West, a period which shows every sign of the Oriental influence so powerful at Rome under the rule of the exarchs of Ravenna. This influence is apparent not only in the more ornate form of the music, but in the frequent use of the Greek language and in the importation of feasts foreign to the Roman rite. In the seventh century four of the most ancient feasts of the Virgin--the Purification, Annunciation, Assumption, and Nativity--were brought from the Orient, and from the same epoch dates the adoption at Rome of the feast called the Exaltation of the Cross, which originated in the Oriental church. 'By the seventh century,’ says Gevaert, 'we are in the presence of an advanced art, conscious of its principles, with rules and formulas for each class of composition.’ Skilled interpreters had been developed by the _Schola Cantorum_, and these, together with the Syrian monks who fled to Italy after the Mussulman conquest, were the real authors of the responses of the nocturnal office and the true chants of the mass. The popes of the seventh century, most of whom were themselves versed in the _cantilena romana_, were particularly solicitous about the beauty and order of the liturgy. To the eleven popes of Hellenic origin who held the chair of St. Peter between 678 and 752 is probably due the final development and perfection of liturgical forms. Chief among them was Agathon (678-681), who seems to have regulated or fixed definitely the texts of what in the eighth century was called the Responsal, or actual Antiphonary, containing the complete repertory of the office of the hours for the entire year. The Venerable Bede says that Agathon sent the leader of the Basilica singers to England to organize that part of the ecclesiastical service according to the usage of Rome. Leo II, we learn from the papal chronicles, was very learned in the sacred chant, as was also Sergius II. The latter, our authority thinks, inspired the last work on the Roman Gradual, and was the first to initiate the Roman singers in the doctrine of the four double ecclesiastical modes, which later writers, following the lead of Boethius, identified with the eight tonal steps