"Until the mid-sixteenth century, the Baths of Diocletian, which today overlook Piazza della Repubblica, appeared to be only a pompous ancient heritage.In 1561, Pope Pius IV de' Medici (1559-1565), at the instigation of the Sicilian priest Antonio Lo Duca devoted to the cult of angels, decided to have a church built inside the Baths.An 86-year-old Michelangelo was responsible for the construction. The great artist designed the church by integrating the sacred building into the baths, without altering the Roman structure of the rectangular hall over 90 meters long; for the apse, he used the natatio, which is the outdoor cold water pool of the baths complex. The façade, with its unique concave brick shape, is one of the ancient exedrae of the calidarium of the baths.On 18 February 1564, on Michelangelo's death, the works were continued by Jacopo Del Duca, his pupil, and nephew of Antonio Lo Duca.The interior of the Basilica is composed as follows: from the entrance, you enter a round vestibule with two square exedras, the ancient tepidarium, while the transept is in the central hall of the baths. It has maintained the ancient solemnity with the eight columns of red granite and the high vaults.On the splendid floor, you can admire the Meridiana or Clementine Line, inaugurated in October 1702 by Pope Clement XI, and the work of Francesco Bianchini. He took inspiration from the work of the great astronomer Gian Domenico Grassini to create it.The sundial is a long bronze line inserted in a marble band, extending for about 45 meters. On the sides, with inlays of polychrome marble, you can admire, on the right, the zodiacal signs of the Summer and Autumn constellations and, on the left, those of the Spring and Winter constellations. At both ends are the zodiac signs of Cancer and Capricorn. The image of the sun, penetrating through the center of the coat of arms of Clement XI, runs throughout the year, starting from Cancer at the Summer Solstice and reaching Capricorn at the Winter Solstice; subsequently, it takes the opposite path.
Over the centuries, the Basilica underwent several changes, including that by Luigi Vanvitelli. In 1750, he designed the facade on Piazza Esedra - now Piazza della Repubblica - the only entrance from which today you can access the church.
In 1911, the Vanvitellian façade on Piazza Esedra was demolished to restore the suggestive niche of the calidarium with Roman bricks. This intervention, however, made the church less visible because it is often mistaken for ruin.
In 1998, the Municipality of Rome donated a new monumental organ to the Basilica, built by Bartolomeo Formentelli, a craftsman from Verona.
In 2001, the Italian-American artist Narcissus Quagliata, a De Chirico pupil, installed a stained-glass dome on the ceiling of the Basilica. The large glass structure, placed 23 meters high, has a diameter of five meters. It also acts as a sundial. You can follow the movement of the earth around the sun by observing its reflection on the floor of the round hall
Inside the church, there is a pleasant permanent exhibition which, through graphics, drawings, and beautiful black and white didactic photographs, tells the story of the Baths of Diocletian and their transformation into a church by Michelangelo."

Misiu martino

"The Basilica of St. Mary of the Angels and of the Martyrs in Rome was a spectacular site that my wife and I found both awe-inspiring and deeply moving. Built within the ancient frigidarium of the Baths of Diocletian—the largest bath complex of Imperial Rome—the church was masterfully redesigned in the 16th century by Michelangelo, who preserved much of the original Roman architecture while adapting it into a grand place of Christian worship. One of the basilica’s most remarkable features is the meridian line, a solar clock installed in 1702 by Francesco Bianchini under the commission of Pope Clement XI. This line, made of bronze and inlaid in the marble floor, runs precisely north to south and includes zodiac signs and dates; it was used to measure solar noon and to determine the date of Easter with incredible accuracy by tracking the sun’s rays as they pass through a small hole in the wall. The basilica is also home to several important relics, including fragments of the True Cross, the bones of early Christian martyrs, and relics of Saints such as St. Sebastian and St. Lawrence. These sacred items are displayed in ornately decorated chapels and reliquaries throughout the church, offering a deeply spiritual connection to the early centuries of Christianity. The combination of ancient Roman engineering, Renaissance artistry, and religious reverence made our visit to this basilica an unforgettable highlight of our time in Rome."

Kirk Belmont

"This Basilica of Saint Mary it was under restoration, but you can actually get to see and walk around it. There are some amazing frescoes by Michelangelo, and there are a lot of chapels around Basilica. Except for the architecture and the style I did, I liked the organ in its usual style and the sundial it was good to see"

Angie O