The Basilica of Saint Cecilia in Trastevere is dedicated to the Christian martyr venerated as an example of devotion. Cecilia was a young woman from a noble Roman family in the 2nd century, the wife of Valerian. She converted to Christianity and took a vow of chastity and devotion to God. She worked tirelessly to convert Valerian and his brother, Tiburtius, and for this she endured three days of torture in the caldarium of the family home. On the third day, having survived the scorching steam, she was beheaded by order of Emperor Alexander Severus.

The church stands on the very site of her martyrdom, Cecilia's family home, a place documented as early as the 5th century as the Titulus Caeciliae, a building where Christian rites were performed. In the 6th century, Pope Gregory the Great built the original basilica. Later, at the beginning of the 9th century, Pope Paschal I had the church built in the basilica form we still see today: a central nave supported by twelve columns connected by arches and a semicircular apse. According to legend, the pope had a vision of Cecilia in a dream, revealing her burial place to him. Her relics were recovered and moved to the very site of her martyrdom, where he built the basilica.

In the 12th century, Pope Paschal II built a monastery also dedicated to Saint Cecilia and Saint Agatha, along with the bell tower (now slightly leaning), and the portico.
During renovations carried out in 1599 by Cardinal Paolo Emilio Sfondrati, the marble tomb and the cypress coffin inside were opened: the saint's almost intact body was discovered, dressed in white and with the marks of her wounds on her neck. The event was considered miraculous, so much so that Pope Clement VIII commissioned the sculptor Stefano Maderno to reproduce the figure as it had been found. The exceptional marble sculpture we can admire on the basilica's high altar reproduces the saint's small body in the same position in which she was found: lying on her right side with her head turned back, covered by a draped cloth and with three cuts on her neck testifying to her martyrdom.

In 1724, the basilica underwent a major renovation at the behest of Cardinal Francesco Acquaviva d'Aragona, who commissioned Ferdinando Fuga to renovate the monumental façade with four pink granite columns. The cardinal's name is clearly visible on the façade's cornice. Fuga created the large courtyard between the monastery and the church, in the center of which the Roman cantharus (cinerary vessel) previously located on the right side was later placed.
Inside the basilica are frescoes of the Last Judgement by Pietro Cavallini, painted in the late 13th century. On the vault, the fresco of the Apotheosis of Saint Cecilia was created in 1727 by Sebastiano Conca.
In the Chapel of the Relics are paintings by the young Luigi Vanvitelli. On the altar of the Bath Chapel are two works by Guido Reni: the Beheading of Saint Cecilia and The Mystical Marriage of Cecilia and Valerian, painted in 1601.

Another masterpiece is the extraordinary ciborium by Arnolfo di Cambio, a combination of architecture and sculpture created in 1293. In Gothic style, it consists of four black and white marble columns topped with statues of Saints Cecilia, Valerian, Tiburtius, and Urban.
In the apse is a mosaic depicting the Blessing Redeemer with Saints Paul, Cecilia, Peter, Valerian, and Agatha, along with Pope Paschal I.

Excavations beneath the church, carried out during the 1899 restoration, uncovered the remains of a 2nd-century BC domus, of which the black-and-white mosaic floors remain, and a small internal bathhouse. The crypt was embellished with gold mosaics and gray granite columns. On the left wall we find the niche where Pope Paschal I found the body of the saint: a copy of Maderno's statue has been placed in the niche, while the original can be admired under the basilica's main altar.