Culture ministry officials on Monday showed reporters where work on the city's third subway line unearthed barracks for Roman Praetorian guards dating back to the second century A.D. (AP Photo/Alessandra Tarantino)

The barracks, discovered nine meters (about 30 feet) below street level, cover 900 square meters (9600 square feet) and include a long hallway and 39 rooms decorated with black-and-white mosaics on the floors and frescoed walls. A view of ancient Roman ruins is pictured above (AP Photo/Alessandra Tarantino)

Officials hope to incorporate the discovery into the new metro station, which is scheduled to open in 2020.

The Praetorian Guard, who are thought to have once lived among these barracks, were prestigious military troops established by the 2nd century BC.

They were household troops of the Roman emperors and acted as bodyguards to generals.

Praetorian Guards served notable figures including Julius Caesar and Mark Antony.

Over the years, the legion evolved greatly to one day become a powerful political force.

In the year 312, the Praetorian Guard was disbanded by Constantine I.