A team of archaeologists has uncovered the ruins of an ancient pagan temple from the Roman period in Italy.

The temple was found during excavations in the ancient hilltop town of Spello, which is located more than 70 miles north of Rome. The structure is thought to date to the fourth century during the reign of Emperor Constantine, who ruled Rome between A.D. 306 and A.D. 337.

Constantine was the first Roman emperor to convert to Christianity. The researchers say the latest findings, announced at the annual meeting of the Archeological Institute of America, shed new light on the transition from the worship of pagan gods to Christianity within the Roman Empire.

During their excavations, the researchers uncovered three walls of a monumental structure that evidence suggests belonged to a Roman temple.

Douglas Boin, a researcher at Saint Louis University who led the excavations at Spello told Newsweek the temple was a “remarkable” historical discovery.

The temple ruins in Spello, Italy. The temple is thought to date to the 4th century during the time of the Roman Emperor Constantine.DOUGLAS BOINNEWSLETTERThe BulletinYour daily briefing of everything you need to know By clicking on SIGN ME UP, you agree to Newsweek’s Terms of Use & Privacy Policy. You may unsubscribe at any time.

“It shows the continuities between the classical pagan world and early Christian Roman world that often get blurred out or written out of the sweeping historical narratives,” he said in a press release.

Boin and his team uncovered the temple during excavations this summer. The researchers had decided to study the area based on a 4th century inscription attributed to Emperor Constantine. The ancient inscription, which was found at Spello in the early 1700s and is now on display in the town hall, indicated that the temple’s construction was an “enormous” undertaking.

In the inscription addressed to the townspeople of the settlement—which became a Roman colony in the 1st century B.C.—the emperor said they would be allowed to celebrate a religious festival in their hometown rather than travel a great distance to another festival.

But in order to do so, the emperor said the town must erect a temple to Constantine’s divine ancestors, the Flavian family, and worship them. This practice formed part of the Roman imperial cult, in which emperors and some members of their families were worshipped as divine entities for centuries.

“There was no separation between religion and state in the Roman world, and Romans’ proud sense of patriotism informed all of their public activities, including their worship,” Boin told Newsweek. “In an empire where people spoke multiple languages, lived across three continents, and held on to their own local traditions, the imperial cult brought people together around common ideals.”

The temple would have been used by the pagan residents of Spello during Constantine’s time, Boin said. It was likely erected in the A.D 330s and dedicated to the cult of the Flavian family to honor the emperor’s ancestral line.

Scholars had long suspected the temple’s existence, but archaeologists had never identified its precise location. The monumental building that the team discovered—whose foundations are 4 feet wide and located near an ancient religious sanctuary—fits the available evidence perfectly for being Constantine’s temple, according to Boin.

“It would have remained in use as a site for worship and religious activities for at least the next two generations until Christians outlawed all pagan religion,” he said.

The temple is evidence of “remarkable” religious continuity between the Roman world and the early Christian world, according to Boin.

“Things didn’t change overnight. Before our find, we never had a sense that there were actual physical, religious sites associated with this late ‘imperial cult practice.’ But because of the inscription and its reference to a temple, Spello offered a very tantalizing potential for a major discovery of an imperial cult underneath a Christian ruler,” he said in the press release.

The discovery of the temple represents the largest evidence ever uncovered of the imperial cult in 4th century Italy and the late Roman Empire, according to Boin.

“There’s evidence from other places throughout the Roman world that Christian rulers supported imperial cult practices,” Boin said. “We’ve known that pagans worshiped at their temples in the 4th century, but those findings have all been small and inconsequential. And we’ve known that Christians supported the imperial cult.

“This temple bridges those two landmarks, and in that respect, it is unlike any temple that I know about from the Mediterranean world of the 4th century Roman Empire. Any study of the imperial cult in the 4th century Roman Empire is now going to have to take account of this temple, which is an incredible discovery to make.”

A map shows the location of the town of Spello, in Umbria, Central Italy.© OpenStreetMap contributorsSpello10 milesNItalyItalyA map shows the location of Spello, in Umbria, Central Italy. Spello is a medieval hilltop town located more than 70 miles north of Rome.Chart: Ian RandallCreated with Datawrapper

Boin said the discovery indicates how societal changes in Roman times took place very slowly. Even though Constantine was the first emperor to convert to Christianity, it did not become the official religion until around 70 years later. In this period, those who worshipped pagan gods gradually converted to Christianity.

“This [discovery] changes everything about how we perceive the pace of social change and our impression of the impact of social and cultural change,” Boin said.

“This building, in a very radical way on its own, shows us the staying power of the pagan traditions that had been on the ground for centuries prior to the rise of Christianity. We are on the cusp of giving people a very visible piece of evidence that really upends the neat and tidy ways people think about big moments of cultural change.”

“This building at Spello shows us quite vividly that Rome’s first Christian emperor, Constantine, continued the established imperial cult practices of his predecessors. That is a remarkable historical discovery,” Boin told Newsweek.

“It shows us that the path from paganism to Christianity was filled with all sorts of strange detours and odd cultural mixing, not all of which would be remembered fondly by authorities in the later church. Just as pagan Romans blended patriotism, imperial ideology, and religion, Christian Romans in Constantine’s time did the same.”