The Arch of Constantine, as much a Roman landmark as the Colosseum, was built nearly 200 years earlier than previously thought, Italy's Central Restoration Institute said Tuesday.
The arch, next to the Colosseum at the south end of the Imperial Forum, was long thought to have been erected in the year 315 in honor of the Emperor Constantine's military victory over rival Maxentius three years earlier.
But after more than 10 years of excavations and surface studies, archaeologists now say they've got to the bottom of the origin of antiquity's most famous triumphal arch.
"The entire bottom half _ that is, the arch itself _ was constructed in the first half of the second century, most likely under the Emperor Hadrian," said Angela Maria Ferroni, one of three members of the excavation team.
"By identifying two different phases of work on the arch, we were able to draw this conclusion," Ferroni told Reuters.
Hadrian ruled Rome from 117 to 138.
The top part of the arch bears an inscription of the Roman Senate's dedication of the arch in 315 to Constantine. Built during the second phase, it dates to Constantine's reign from 306 to 337.