The Basilica of San Pietro de Dom was a church in Brescia built in the early Christian era on the east side of the Piazza del Duomo.

[3] Based on the use of Roman elements in its construction as well as the basilical form, Panazza avers that the church originates between the sixth and eighth centuries, when the builders used ancient materials found on the spot.

[5] Between 1571 and 1581, the edifice underwent extensive renovation: the floor was raised to the level of the square, windows were installed and a new roof with a false ceiling created.

The building did not survive very long thereafter: it was structurally unstable and deteriorating, and within about twenty years, it was demolished to allow the construction of a larger church, the New Cathedral, which was more in line with the aesthetic of the period.

The first is the miniature on the cover of the Estimo della città di Brescia of 1588, which depicted the eastern side of the Piazza del Duomo, showing the Broletto palace with the Torre del Popolo tower, the Old Cathedral with its campanile (which collapsed in the 18th century), and the basilica itself in an emerging central body with two lower side aisles covered by sloping roofs.

An example is the Francesco Maffei painting Transporting the reliquaries of the Brescian saints Anastasio, Dominatore, Paolo and Domenico (currently in the Old Cathedral), where one can see the basilica's facade with the roseate window, as well as the south side with its series of arches typical of the period.

[8] A Pompeo Ghitti painting Beato Bernardino da Feltre istituisce a Brescia le scuole del SS.

These originated in the Roman era and comprised the colonnade between the main and the two side aisles: monolithic columns of dark Egyptian marble, described by Zamboni as coloured like iron.