Researchers discover ancient temple ruins thanks to Emperor Constantine's letter to group of Romans

Some 1,600 years ago, a group of Roman Empire citizens in Italy received a letter from Emperor Constantine, allowing them to celebrate a religious holiday in their hometown rather than traveling to a faraway festival, the Miami Herald reports.

Experts discovered Constantine’s response, known as a rescript, in the 18th century—and archaeologists have just used it to make a “monumental discovery.”

A team of researchers from Saint Louis University unearthed “three walls of a monumental structure that evidence suggests belonged to a Roman temple that dates to Constantine’s period,” Douglas Boin, a history professor at Saint Louis University, said in a university news release.

The ruins were found in Spello, a “famous medieval hilltop city,” the university said. They date to Constantine’s rule of the Roman Empire, which was between 324 A.D. and 337 A.D.

Constantine was famously the first Roman emperor to practice Christianity. But his request to the Spello people reflects “Imperial Cult” beliefs, indicating that the transition from paganism to Christianity was not a quick one, experts said.

The “Imperial Cult” is also known as the “Cult of Emperor,” according to the Harvard Divinity School. It involves “the worship of Emperors and their families as divine” which began with Julius Caesar’s death in 44 B.C.