Church built on Roman street paving may be lost cathedral of Altino, near Venice

In brief 3 key points

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• A large church from around AD 400 was excavated at Altino.
• It may be the city's lost first cathedral and bishop's palace.
• The church identification rests on clues and is a working hypothesis.

Archaeologists at Altino, the Roman city of Altinum on the edge of the Venetian lagoon, have found a large late Roman church. They think it was the city's first cathedral. It dates from the late 4th to the early 5th century AD, and a second large building beside it may have been the bishop's palace.

The results were presented on 22 October at a study day at the National Archaeological Museum of Altino. The work involves the Archaeological Park of Altino, the universities of Padua and Trento, and Ca' Foscari University of Venice. The regional heritage office (Soprintendenza) for the metropolitan city of Venice also takes part. It was the second such meeting, after one held the year before.

Found by rereading old excavations

Altino had a bishop in the 4th century AD. Diego Calaon of Ca' Foscari University said its first bishop, St Heliodorus, was a real historical figure. He is known from his letters exchanged with St Jerome. Earlier accounts described a populous city and a richly decorated church, but the church had never been found.

Calaon's team used GIS mapping software to gather data from excavations of the 1960s, 1970s and 1980s that showed signs of late antique activity. This revealed a wall built of overturned paving stones, set at an odd angle to the Roman houses around it. Test trenches then exposed a large rectangular hall, 32 by 20 metres, with a portico across its front.

Calaon compared the hall in size with the first hall at Aquileia, the great Roman port further east. The main clue to its purpose was the foundations. They were built from real paving stones taken up from the city's streets. In Calaon's view, only a public authority, in this case the bishop, could have had the power to dismantle a street.

A possible bishop's palace and burials

The hall has no apse. East of it, however, lies another large building with even deeper foundations, also made of paving stones. The team thinks it was a smaller room built to some height. There are signs it had a portico on at least one side. Fragments of coloured mosaic found out of context are thought to come from it, and it may have been the bishop's palace.

Many burials were concentrated in the narthex, the entrance hall of the church, and in the eastern building. The team suggests an important burial drew other members of Altino's religious community to be buried nearby.

Only robbed-out foundations survive. The stone was removed at the end of the 7th century. Calaon said one idea is that the material went to Torcello, an island in the lagoon. The bishop of Altino moved to Torcello during the 7th century, perhaps in connection with the rise of the Lombard kingdom in Italy. One grave held a buckle with late Byzantine imagery but workmanship that Calaon described as almost more Lombard.

Jacopo Bonetto, professor of classical archaeology at the University of Padua, called the basilica a major result. He said what aerial photographs and remote sensing had shown is now being confirmed on the ground. The city's monumental plan dates from late in the reign of Augustus, and the city stayed active throughout the imperial period.

Excavations in 2025 and 2026 have also exposed the forum, a nearby civic basilica and part of one of the city's two theatres. These lie in a large area acquired by the Archaeological Park. Other work covered the harbour gate and its canal, a stretch of the Via Annia road and an ironworking workshop. The old Saggio Barca dig at a small river landing was re-plotted on the map and redated using deep cores.

Marianna Bressan, director of the National Archaeological Museums of Venice and the Lagoon, said Altino has no architectural remains that can be left on view. The city survives as negative imprints left where buildings were taken apart. Their stones and bricks went to Venice, Padua and Treviso. The park is now considering how to present this absence, possibly with planting or contemporary art and architecture.

Sources (1)

News reportsfrom Ca' Foscari University of Venice, University of Padua and University of Trento

• Altino, riaffiora la città sepolta: scoperta la prima basilica episcopale della città (ilgiornaledellarte.com)

Edited by Guiseppe Weijermars

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early christianitylate antiquitychurchesroman italyvenice lagoon

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