The archive is located inside the 12th century Episcopal Seminary of the town of Segni, in the upper part of the town where the acropolis once stood. The building had been built by Pope Eugenius II who had lived there and other popes such as Lucius III, Alexander III and Innocent III, to whom it is dedicated, also stayed here for a short time.
The building was transformed into a diocesan seminary in 1709 and in the nineteenth century it was expanded with a new wing that now houses the Innocent III Archives.
The archives contain all the documents of the church from the fifteenth century: archives of the Chapter, bishop archives, marriage records and civil acts. The archive is very active in promoting the area around Segni through the rediscovery of its history.
For example, an incunabulum was discovered, a book printed with the movable type technique that was used between the mid-fifteenth century and the year 1500, which tells the story of the discovery of the statue of Laocoon. This date is important because it is at the beginning of the Vatican Museums and in their profile the year of the discovery of the statue in a garden is indicated because from this find the immense collection was donated which can now be visited in the Vatican Museum, among the most important in the world.
The sculpture of Laocoon dates back to the first century AD and was believed to have been found in a vineyard on the slopes of Colle Oppio on 14 January 1506. In Segni’s incunabulum is a copy of an edition of the Naturalis Historia by Pliny the Elder printed in Venice in 1491 by the editor Tommaso de’ Blavis, instead, given the discovery on 10 January 1506: gave four days more of life and a birthday for the Vatican Museums.
The story of the discovery with the date in a note next to the text of the book was written by the book’s owner, Angelo Recchia de Barbarano (1486-1558) who was a jurist. He had been in the service of the capitoline magistrature and of the Apostolic Chamber and then of the La Sapienza University conservatories in 1557: he had obtained in 1553 the honorary citizenship of Rome and his grave stone is in the church of Sant’Agostino in Campo Marzio.