From the Martyrology:
Sanctae Caeciliae, Virginis et Martyris, quae ad caelestem Sponsum, proprio sanguine purpurata, transivit sextodecimo Kalendas Octobris.
The memorial of Saint Cecilia, virgin and martyr, who, empurpled in her own blood, passed unto to her heavenly Spouse sixteen days before the kalends of October [16 September].
If we flip a few pages back and check the entry for 16 September, after mention of Pope Martin I, we find:
Romae item natalis sanctae Caeciliae, Virginis et Martyris, quae sponsum suum Valerianum et fratrem ejus Tiburtium ad credendum in Christum perduxit, et ad martyrium incitavit. Hanc Almachius, Urbis Praefectus, post eorum martyrium teneri, atque illustri passione, post ignem superatum, fecit gladio consummari, tempore Marci Aurelii Severi Alexandri Imperatoris. Ejus vero festum recolitur decimo Kalendas Decembris.
At Rome the heavenly birth [earthly death] of Saint Cecilia, virgin and martyr, who led her husband Valerianus and his brother Tiburtius to belief in Christ, causing her martyrdom. Because of this, Almachius, Prefect of Rome, after decreeing their martyrdom and their celebrated suffering, and after she survived the flames, had her killed by the sword, in the time of emperor Marcus Aurelius Severus Alexander. Her true feast is commemorated on 22 November.
Even the ancient Martyrologium Hieronymianum for 16 September reads: Appia via in eadem urbe Roma natale et passio sanctae Caeciliae virginis. So if the date of Cecilia’s death was known even in Christian antiquity, why the disparity between her natale and her feast?
It seems that what has become St. Cecilia’s Day is really the date in which the Roman basilica of Santa Cecilia in Trastevere was dedicated. According to the oldest extant testimony of her death (from about the fifth century), the property housing the current basilica was owned by Cecilia’s family, and it was here that she died. Yet, the Martyrologium Romanum says Appia via, indicating that, on account of her glorious martyrdom, Cecilia was buried in the Catacombs of Callixtus among the bishops and confessors. It appears that she willed her house to become a temple for worship of the most high God, which Pope Urban obliged. This temple, dedicated on 22 November, is the Basilica of Santa Cecilia in Trastevere, which even in the fourth century was known as titulus Sanctae Caeciliae. The Basilica today is a convent which houses the nuns who weave the pallia presented by the Pope to new metropolitan archbishops on the Feast of Saints Peter and Paul.
The legend, well known, runs as follows: like Agnes and Agatha, Cecilia was another Christian maiden of noble birth who had made a vow of virginity before God. She was arranged to be married to a certain Valerian, a pagan, and when the time for marital consummation was upon her, she pled with Valerian to respect her vow. Cecilia told Valerian of her guardian angel who would punish her if but a finger was laid upon her head. Valerian replied that he would respect the vow if he could see the angel. Cecilia prayed and told her husband that if he went to the catacombs around the third milestone on the Via Appia to find a bishop named Urbanus (Pope St. Urban I), he would see the angel. Through Cecilia’s prayers and Urban’s preaching, Valerian was brought to the Christian faith and baptized by Urban himself. Valerian’s brother Tiburtius was also received into the Church.
Though the emperor Severus Alexander generally tolerated the Christian minority, it seems that the prefect of Rome, Turcius Almachius, was a more severe man. Upon hearing of Valerian’s conversion, he had Valerian, Cecilia, and Tiburtius locked in the bath house of Cecilia’s estate and had it burned. Valerian and Tiburtius died of suffocation, but Cecilia survived (ignem superatum). The executioner then went to behead Cecilia, but somehow the execution was botched. Three times he struck her, and three times his sword failed to slice though the neck. Nevertheless, Cecilia bled profusely, and the executioner left her for dead. Brought back into the remains of the house, she remained alive for three days, long enough for Pope Urban to visit and hear her wish that a church be built on her destroyed property. Drenched in her own blood (proprio sanguine purpurata), she died lying on her side; unable to speak in her final moments, she made of her hands a defiant profession of faith. With one hand, she extended her index finger; with the other, she extended the index, thumb, and middle. For any Christian of antiquity, the message was clear: Cecilia confessed One God in Three Persons.
In the ninth century, Pope Paschal I brought Cecilia’s relics (along with those of Valerian and Tibertius) from the catacombs back to her basilica in Trastevere, where with great ceremony they were reinterred under the high altar. Various renovations eventually obscured the tombs until the 1599 renovation under Paolo Sfondrati, Cardinal-Priest of Santa Cecilia, in preparation for the Jubilee of 1600. When the supposed sarcophagus of Cecilia was opened, Cardinal Sfondrati and his witnesses beheld a moving sight: it was the body of the saint, incorrupt, lain gently on its side, as if sleeping peacefully. Her hands, made cold by the passing of centuries, still silently gestured that ardent, undying faith in the holy and undivided Trinity,
The magnitude of this discovery was not lost on Sfondrati: he quickly commissioned Stefano Maderno, younger brother of the illustrious Carlo, to depict the body in marble exactly as she was discovered. The result is Maderno’s famous Santa Cecilia depicted above. Its stark simplicity stands in contrast to the dramatic imbalances of Mannerism which had swept Italy at that time, further supporting the idea that the sculpture was indeed not an ex nihilo creation of Maderno (a Mannerist student who would help usher the Baroque) but a faithful representation of the saint.
Like Agnes and Agatha, Cecilia’s memory has survived her death. Alexander Severus and Almachius are mere footnotes in the annals of history, while countless, churches, sculptures, and paintings of this young virgin martyr decorate so many places on this earth. Even more women are adorned by her most glorious name. She did not win this acclaim by submission to a hostile world, and even when her voice was silenced, her bloodied hands spoke even more eloquently of the love she held most dear. This vehement, unyielding adherence to the Creed is the strength which sustained Cecilia despite her trials, a strength tragically lacking in so many churches today, where the Creed is often recited with lackadaisical indifference. Should, quod Deus advertet, militants of Boko Haram or ISIS challenge our faith at gunpoint, shall we with ease abandon the treasure bequeathed by Christ? I pray that we should not! When at Mass we recite a profession of faith, let us remember the testimony of Cecilia, a young girl who, proprio sanguine purpurata, despite the silence of her tongue, loudly confessed the Triune God at the moment of death.