The Theatre of Epidaurus: the theatre that carries a whisper

Epidaurus was a small city-state on the Saronic Gulf. A few kilometres inland, in a green valley, it had a famous sanctuary of Asklepios, the god of medicine. Sick people travelled there from all over Greece. They prayed and then slept in a special hall, the ἄβατον, a place where only those allowed could enter. They hoped the god would visit them in a dream and show them a cure.

The sanctuary was not only a place of prayer. It had temples, baths, guest houses, a stadium and a theatre. The Greeks believed that music, games and plays were part of the god's θεραπεία, his care for the sick. In Pausanias' time (2nd century AD) stone slabs in the sanctuary still listed the names of men and women who had been healed, their illness and their cure. UNESCO calls the site an early example of the move from healing by the gods to the science of medicine, and listed it as World Heritage in 1988.

The seats rise up the slope of Mount Kynortion like a giant stone bowl. This part is called the κοῖλον, the “hollow”. It has two parts. The lower part, built in the 4th century BC, has 34 rows of stone benches. The upper part, with 21 more rows, was added around the middle of the 2nd century BC. Between them runs a curved walkway, the διάζωμα. Narrow stairs cut the bowl into wedge-shaped blocks of seats, each a κερκίς. In all the theatre held about 13,000 to 14,000 spectators; some sources give a lower figure of about 12,000.

At the bottom lies a perfectly round dancing floor, about 19.5 metres across. Behind it stood the stage building, which survives only in its lower parts. Unlike most Greek theatres, Epidaurus was not rebuilt by the Romans, so it keeps its original shape.

The traveller Pausanias (Description of Greece 2.27.5) praised its symmetry and beauty and said it was built by Polykleitos. Most scholars think he meant a younger architect of that name, not the famous 5th-century sculptor, but this cannot be proved. The theatre was excavated from 1881 by Panagis Kavvadias and restored in the 20th century.

Tour guides like to drop a coin or tear a sheet of paper in the middle of the dancing floor, while visitors listen from the top rows. The theatre's acoustics, ακουστική in Greek, are famous. The word goes back to ἀκούω, “I hear”, and came into Modern Greek through French. But what really makes the sound so good?

In 2007 two researchers at the Georgia Institute of Technology, Nico Declercq and Cindy Dekeyser, published an answer in the Journal of the Acoustical Society of America. Their tests and computer models suggested that the rows of limestone seats work like a filter. They hold back low sounds, such as the murmur of the crowd, and reflect the higher sounds of a voice back towards the audience. Our brain fills in the missing low notes, as it does on the telephone.

In 2017 a team from Eindhoven University of Technology measured the theatre at hundreds of points. Their results were more modest. A coin or tearing paper could be recognised only about halfway up, and a whisper only near the front, so the ἠχώ of the legend is partly a myth. An actor who projects his voice still carries far, though. The researchers stressed that they measured the worn stones of today: the polished seats of antiquity may have sounded better.

For centuries the theatre lay under earth and trees. The first modern performance came in 1938: Sophocles' Electra, directed by Dimitris Rontiris, played in the afternoon light because there was no electricity. The Second World War stopped the plan for a yearly season. In 1954 Euripides' Hippolytus opened the festival, and from 1955 it became an annual event, today part of the Athens Epidaurus Festival.

Since then great names have come here. The soprano Maria Callas sang Bellini's Norma in 1960 and Cherubini's Médée in 1961. In 1975 Karolos Koun's Art Theatre brought Aristophanes' Birds and Aeschylus' Persians.

Today the festival comes back every summer. Thousands of spectators climb the old steps at sunset, and buses leave Athens for the theatre on performance days. Most plays are given in Modern Greek translation, often a new one, with Greek and English surtitles; visiting companies sometimes play in their own language. In this way the plays written for Athens 2,500 years ago still meet a living Greek-speaking audience.