Rome set to open more subway museums.

A rare representation of the goddess Roma on ancient gold glass has emerged during construction works for Rome's third subway line, the city has announced.

Originally the base of a drinking glass, the discovery features an image of the female deity - the personification of the city of Rome - wearing a helmet and carrying a spear.

It is the first time that any representation of Roma in gold glass has ever been found, according to archaeologist Simona Morretta of Rome's special superintendency.

Describing it as "extraordinarily refined", Morretta told news agency ANSA: "Golden glass is already a very rare find, but this has no comparison".

Gold glass is a luxury form of glass where a decorative design in gold leaf is fused between two layers of glass. The majority of surviving Roman examples are the cut-off bottoms of drinking glasses.

Gli scavi per la realizzazione della #MetroC hanno riportato alla luce straordinari reperti archeologici. Tra questi, il fondo di una coppa in vetro dorato con la personificazione di #Roma. La storia millenaria della nostra città non smette mai di stupire e incantare il mondo. pic.twitter.com/AViY2Eu3Mk

— Roberto Gualtieri (@gualtierieurope) February 2, 2023

Morretta said the precious artefact did not belong to the military barracks found during the subway works - which was abandoned in the middle of the third century and subsequently razed to the ground - with preliminary studies suggesting the glass is from the start of the fourth century.

The unprecedented discovery, made during excavations for the Metro C station at Porta Metronia, was hailed by Rome mayor Roberto Gualtieri who wrote on Twitter: "The milennial history of our city never ceases to amaze and enchant the world."

During a site visit on Thursday, Gualtieri said that Porta Metronia would be another "metro station-museum" - displaying the archaeological finds yielded during its construction including the gold glass - similar to the preceding Metro C station at S. Giovanni.

The mayor also said that Porta Metronia would be open in late 2024, in time for the Jubilee 2025, followed by the opening of the next Metro C station at the Colosseum.

The driverless 19-km Metro C line currently comprises 22 stations and runs from Pantono in east Rome to S. Giovanni, where it connects with Metro A and the central Termini train station.

With the opening of the Colosseo station, Metro C will connect with the Metro B line.

Construction is set to begin on the Metro C station at Piazza Venezia during the first half of 2023, the city said recently.

The Venezia metro stop has a planned completion date of 2030, according to Gualtieri, who added that it too would be a "station-museum".

The latest archaeological discovery announced by the city comes a week after a statue of an elderly figure in the guise of Hercules - possibly Emperor Decius - was found during sewer works near the Appian Way which is currently seeking UNESCO World Heritage Status.