The building was started with the use of materials from monuments of various civilizations, including the Roman, Lombard and Jewish. Its design dates back to the twelfth century, when the Ancient Church was deemed an unsuitable place to hold the growing number of followers, so it was decided to engineer a vast expansion behind the apse, with the aim of creating a single large basilica.
It is said that the works, subsidized by the Benedictines, began in mid-1100, but the pace gradually diminished, due to the heritage of the Benedictines and also because they were forced to abandon Venosa due to the suppression of their monastery at the behest of Pope Boniface VIII in 1297. This was due to the "Knights of the Order of the Hospital of St. John of Jerusalem" (hereinafter known as the Knights of Malta), who lost their possessions in Palestine during the Last Crusade .
The Order did not pay attention to the system of the new monastic church and settled its headquarters in Venosa, precisely in the "Palace of the Bailiff." Since that time, the structure was never completed. However, other interventions were implemented as the portal in the fourteenth century and the bell tower in the sixteenth century, but at the architectural level the Unfinished Church remained so. Today the monument is entrusted to the ancient order of the Trinitarian Fathers.