From the Catholic Encyclopedia:
About the middle of the fifth century originated Acts of the martyrdom of St. Cecilia which have been transmitted in numerous manuscripts; these acts were also translated into Greek. They were utilized in the prefaces of the above-mentioned masses of the "Sacramentarium Leonianum". They inform us, that Cecilia, a virgin of a senatorial family and a Christian from her infancy, was given in marriage by her parents to a noble pagan youth Valerianus. When, after the celebration of the marriage, the couple had retired to the wedding-chamber, Cecilia told Valerianus that she was betrothed to an angel who jealously guarded her body; therefore Valerianus must take care not to violate her virginity. Valerianus wished to see the angel, whereupon Cecilia sent him to the third milestone on the Via Appia where he should meet Bishop (Pope) Urbanus. Valerianus obeyed, was baptized by the pope, and returned a Christian to Cecilia. An angel then appeared to the two and crowned them with roses and lilies. When Tiburtius, the brother of Valerianus, came to them, he too was won over to Christianity. As zealous children of the Faith both brothers distributed rich alms and buried the bodies of the confessors who had died for Christ. The prefect, Turcius Almachius, condemned them to death; an officer of the prefect, Maximus, appointed to execute this sentence, was himself converted and suffered martyrdom with the two brothers. Their remains were buried in one tomb by Cecilia. And now Cecilia herself was sought by the officers of the prefect. Before she was taken prisoner, she arranged that her house should be preserved as a place of worship for the Roman Church. After a glorious profession of faith, she was condemned to be suffocated in the bath of her own house. But as she remained unhurt in the overheated room, the prefect had her decapitated in that place. The executioner let his sword fall three times without separating the head from the trunk, and fled, leaving the virgin bathed in her own blood. She lived three days, made dispositions in favour of the poor, and provided that after her death her house should be dedicated as a church. Urbanus buried her among the bishops and the confessors, i.e. in the Catacomb of Callistus.
Like so many Roman saints, the inevitable conflict with authority that leads to martyrdom. The Catholic Encyclopedia adds this note:
In this shape the whole story has no historical value; it is a pious romance, like so many others compiled in the fifth and sixth century.
Of course, how the Encyclopedia claims to know this is not explained. The possibility that a story could be handed down orally for a few hundred years before being written down is not, in and of itself, a reason for disbelieving the story. There is doubtless much in the martyrology of which to be skeptical, but martyrdom is a real possibility for Christians even in this day and age (go preach the gospel of Matthew on a street corner in Riyadh if you doubt this), and skepticism is a poor companion to take with you on a final journey. At any rate, as the encyclopedia relates, she is a saint held in veneration by the Romans from antiquity:
This saint, so often glorified in the fine arts and in poetry, is one of the most venerated martyrs of Christian antiquity. The oldest historical account of St. Cecilia is found in the "Martyrologium Hieronymianum"; from this it is evident that her feast was celebrated in the Roman Church in the fourth century. Her name occurs under different dates in the above-mentioned martyrology; its mention under 11 August, the feast of the martyr Tiburtius, is evidently a later and erroneous addition, due to the fact that this Tiburtius, who was buried on the Via Labicana, was wrongly identified with Tiburtius, the brother-in-law of St. Cecilia, mentioned in the Acts of her martyrdom. Perhaps also there was another Roman martyr of the name of Cecilia buried on the Via Labicana. Under the date of 16 September Cecilia is mentioned alone, with the topographical note: "Appiâ viâ in eâdem urbe Româ natale et passio sanctæ Ceciliæ virginis (the text is to be thus corrected). This is evidently the day of the burial of the holy martyr in the Catacomb of Callistus. The feast of the saint mentioned under 22 November, on which day it is still celebrated, was kept in the church in the Trastevere quarter at Rome, dedicated to her. Its origin, therefore, is to be traced most probably to this church. The early medieval guides (Itineraria) to the burial-places of Roman martyrs point out her grave on the Via Appia, next to the crypt of the Roman bishops of the third century (De Rossi, Roma sotterranea, I, 180-181). De Rossi located the burial-place of Cecilia in the Catacomb of Callistus in a crypt immediately adjoining the crypt or chapel of the popes; an empty niche in one of the walls contained, probably, at one time the sarcophagus with the bones of the saint. Among the frescoes of a later time with which the wall of the sepulchre are adorned, the figure of a richly-dressed woman appears twice and Pope Urban, who was brought personal into close relation with the saint by the Acts of her martyrdom, is depicted once. The ancient titular church of Rome, mentioned above was built as early as the fourth century and is still preserved in the Trastevere. This church was certainly dedicated in the fifth century to the saint buried on the Via Appia; it is mentioned in the signatures of the Roman Council of 499 as "titulus sanctae Caeciliae" (Mansi, Coll, Conc. VIII, 236). Like some other ancient Christian churches of Rome, which are the gifts of the saints whose names they bear, it may be inferred that the Roman Church owes this temple to the generosity of the holy martyr herself; in support of this view it is to be noted that the property, under which the oldest part of the true Catacomb of Callistus is constructed, belonged most likely, according to De Rossi's researches, to the family of St. Cecilia (Gens Caecilia), and by donation passed into the possession of the Roman Church. Although her name is not mentioned in the earliest (fourth century) list of feasts (Depositio martyrum), the fact that in the "Sacramentarium Leoniam", a collection of masses completed about the end of the fifth century, are found no less than five different masses in honour of St. Cecilia testifies to the great veneration in which the saint was at that time held in the Roman Church ["Sacram. Leon.", ed. Muratori, in "Opera" (Arezzo, 1771), XIII, I, 737, sqq.].
St. Cecilia is the patroness of church music, so it is fitting to recall her when considering this story, on how Pope Benedict XVI seeks to revive sacred music, especially Gregorian Chant:
Monsignor Valentin Miserachs Grau, the director of the Pontifical Institute of Sacred Music, believes the entire church should return to Gregorian chance [sic]."Due to general ignorance, especially in sectors of the clergy, there exists music which is devoid of sanctity, true art and universality," he said.
Spoken like a true reformer -- notice at whom the criticism is aimed.
The great thing about Catholicism is that there are no new discussions, only timeless ones. The story is being spun to portray Benedict as being a relic, a dinosaur, hopelessly out of touch with the modern age. And that is precisely why the effort to revive the chant is the correct one. Christianity is always at conflict with the current trends of the age. The sacred always seems out of touch to the profane.