ATHENS, Greece — The ruined theater under the Acropolis where the works of Euripides and other classical playwrights were first performed some 2,500 years ago will undergo partial restoration over the next six years, Greek officials said Wednesday .

The euro6 million ($9 million) program is set for completion by 2015 and will include extensive modern additions to the surviving stone seats of the Theater of Dionysos.

But is unlikely that the site will host modern audiences any time soon.

Standing on the southern slopes of the Acropolis Hill, the theater was first used in the late 6th century B.C. It saw the opening performances of tragedies by Aeschylus, Sophocles and Euripides, as well as Aristophanes’ comedies — considered the precursors of western theater.

“The Theater of Dionysos … is of immense historic significance, as it is here that the masterpieces of ancient drama were first performed,” said architect Constantinos Boletis, the project leader.

Theater first emerged as an art form in late 6th century B.C. Athens, where playwrights competed for a prize during the annual festival of Dionysos — the ancient god of theater and wine in whose cult the art originated.

Originally a terrace where spectators sat on the bare earth above a circular stage, the Theater of Dionysos was rebuilt in limestone and marble during the 4th century B.C. and modified in Hellenistic and Roman times

A small section of the stone seating — which could hold up to 15,000 spectators — survives. Restorers will gradually add several tiers, using a combination of new stone and recovered ancient fragments, while strengthening retaining walls and other parts of the building.

“The program will have a major impact on the overall aspect of the monument,” Boletis told a press conference.

A decades-long project is already under way to conserve and restore the ancient marble temples on the Acropolis, which includes the complete disassembly and rebuilding of the 5th century B.C. Temple of Athena Nike.

The Dionysos project will be funded by a grant from Athens regional authorities, in cooperation with the Diazoma nonprofit foundation for the protection of the estimated 140 ancient theaters and concert halls that survive throughout Greece.

Following extensive restoration over the past century, some now host summer music and theatrical performances.

But there appears little prospect of that happening at the Theater of Dionysos, despite initial plans after its excavation in the 19th century.

“The idea … was finally abandoned in the mid 1970s,” Boletis said.