Archaeologists discovered an ancient theatre lying beneath the remains of the Serdika amphitheatre in Sofia's centre.

Archaeologist Borislav Borislavov described the site, discovered by his colleague Zharin Velichkov as the 'most sensational discovery of the season', Focus news agency reported.

Discovering an earlier theatre beneath the remains of another one was unprecedented, Velichkov said. The theatre was build in second century AD during the reign of emperor Marcus Aurelius Antoninus, also know as Carcalla.

Velichkov is working on the remains of the largest amphitheatre on the Balkans for a second season. The amphitheatre was built in third century AD during the reign of emperors Dioclitian and Konstantine the Great. The arena measures 60.5 metres in width.

The archaeologists would seek additional funding for the excavation of the theatres from the Culture Ministry.