Archaeologists Just Found the Lost Church From a Saint’s 1,600-Year-Old Letter.

Here’s what you’ll learn when you read this story:

• Archaeological excavations in northern Italy’s ancient Altino revealed a church previously only known about through historical writings.
• Researchers uncovered both a church and attached bishop’s palace dated to the fourth century C.E.
• Experts believe the discovery tells the story of the eventual fall of Altino—and the rise of Venice.

Excavations that revealed a fourth-century C.E. church in the ancient city of Altino have finally substantiated a letter written by Saint Jerome in 396 C.E., and they help illustrate the rise of Venice in the wake of Altino’s demise.

Experts had long suspected that a church stood in the ancient Italian city of Altino, thanks to St. Jerome’s letter, but no physical evidence had ever supported the claim, despite ongoing work at the Altino Archaeological Park. The new discovery not only uncovered the rectangular church building but also exposed a bishop’s palace connected to it. Together, the two structures help tell the story of the population shift from Altino to Torcello, the launching point for the rise of Venice.

“For the first time, we can say with a very high degree of confidence where the church and the bishop’s palace of Altino stood,” Diego Calaon, excavation director with Ca’ Foscari University of Venice, said in a translated statement. “Written sources told us they must have existed. Now we have archaeological evidence to support this.”

Those written sources begin with Letter 60, addressed by St. Jerome to Heliodorus, the first bishop of Altino. In it, Jerome describes the site and the care the priest Nepotian lavished on the church, even documenting its altar, walls, floors, curtained doorways, and sacred vessels.

The newly excavated building matches that picture. Roughly 1,600 years old, the late antique church measured 100 feet long and 65 feet wide. Its hall does not align with the Roman street grid, instead facing east, and its lack of an apse fits traditional northern Adriatic architecture. Immediately to the east, excavations revealed the bishop’s palace: the foundations of what was likely a two-story porticoed structure built with stones reused from Roman roads. The residence featured internal walls and annexes, with the second story probably housing clergy and the ground floor hosting privileged burials.

That reuse of trachyte Roman road paving stones—laid upside down—is one of the site’s most telling details, because it establishes the bishop as a key figure in the city. University experts noted that Roman law protected roads as public infrastructure, so repurposing the stone suggests the bishop held considerable sway.

Elisa Possenti, excavation co-director from the University of Trento, said the finds open fresh perspectives. “Thanks to these discoveries, the city can now be considered alongside other major episcopal centers in late antique northeastern Italy,” she said. “What we could only imagine from descriptions in written sources is finally taking physical form. This will help us reassess the lives and roles of Altino’s earliest bishops, whose histories have largely been shrouded in legend.”

Work at the site continues, and the team hopes to uncover more of the church and the bishop’s palace, including the baptistry.

Pinpointing Altino’s early Christian heritage also helps illustrate the demographic movement to Torcello and the shift of the episcopal seat. Once believed to have been a sudden change, the move now appears to have been both gradual and deliberate. Excavations at Torcello show that the island served as Altino’s port, and an inscription in the baptistry there dates the church to 639 C.E. With Torcello on the rise, Altino became a major source of reusable building material, and that trade eventually paved the way for the move to Rialto and the growth of Venice.

“This analysis allows us to tell the story of the transition from Altino to Torcello and Venice in a new way,” Calaon said, “not as a sudden flight, but as a long, managed transformation in which the ancient city and its inhabitants actively shaped economic and political decisions. At the same time, the buildings and spaces of ancient Altino became a source of materials that helped create a new way of inhabiting the lagoon.”

That recycling may also explain the church’s disappearance: experts believe the Altino church and palace were lost to the stripping of stones and bricks for reuse in construction at Torcello and Venice.

Marianna Bressan, director of the National Archaeological Museums of Venice and the Lagoon, said the excavations add important information for understanding these ancient cities. “Research at Altino provides an opportunity to view the city’s history in a broader context,” Bressan said, “tracing the Venetian area’s transformation from antiquity to the formation of the lagoon as we know it today.”