within "the boundaries of this city"; the Masses of the Patrons of Rome, St Peter and St Paul, continually allude to the city. Louis Duchesne concluded that the Leonine book is a private collection of prayers copied without much intelligence from the official books at Rome about the year 538. He arrives at this date especially through an allusion in the Secret of a Mass placed in June (but really an Easter Mass), which refers to a recent deliverance from enemies. This allusion he understands to refer to the raising of the siege of Rome by Vitiges and his Goths at Easter-time, 538. Another writer attributed the allusion to Alaric's invasion in 402, and held that the compilation was made between 366 and 461. Another considered that the book was composed under Pope Felix III (483-492). Yet another suggests that the book is a compilation of Roman Masses made in the sixth or seventh century for use in Gaul, so that the composers of Roman books who were at that time introducing the Roman Rite into Gaul might have a source from which to draw their material. He suggests Gregory of Tours (died 594) as possibly the compiler. The Gelasian Sacramentary The "Gelasian Sacramentary" contains everything needed by a priest in charge of a Roman titular or parish church. The archetype, now lost, was likely written in the mid-7th century, possibly for the Church of St Peter in Chains in Rome. It features modifications introduced by Gregory the Great (590–604) in the canon of the Mass (notably the insertion of the prayer Hanc igitur), but does not yet contain either the Agnus Dei made official by Pope Sergius I (r. 687–701) or the Masses for the Thursdays in Lent added by Pope Gregory II (r. 715–731). The oldest extant copy of the sacramentary, a book now often called the Old Gelasian Sacramentary, Vatican Reg. lat. 316, was made in the 7th or early 8th century for use in the abbey of St Denis at Paris. It includes five interpolated sections that introduce liturgical practices of Gaul from the time the manuscript was copied, but the interpolations are easily distinguished from the Roman sections of the text. The Old Gelasian Sacramentary consists of three books. Book I includes masses for feasts and Sundays from Christmas Eve to the octave of Pentecost (there were at the time no special masses for the