Isthmia (near modern Kyras Vrysi, Greece)

Greek theatre before 390 BCE; Roman enlargement 146 BCE (Sear 399).

Cavea Width: 72 meters
Orchestra Width: 18 meters

The Theatre at Isthmia near Kyras Vrysi, Greece was built before 390 BCE and had Roman-period dimensions of 72m wide cavea and 17.6m orchestra. It featured eight stone rows arranged in seven sections, possibly with wooden upper seating, and could accommodate approximately 1,550 spectators in its lower level. Facing north, the theatre underwent several renovations (late 4th century BCE, after 146 BCE, and during Nero’s reign in 68/69 CE). A planned expansion under Marcus Aurelius was never completed. Today, the structure exists only in fragments, with many parts repurposed in Byzantine buildings.

The Ancient Theater of Isthmia (near modern Kyras Vrysi, Korinthia, Greece)

The ancient theatre at Isthmia is situated in the northeastern section of the Sanctuary of Poseidon near modern Kyras Vrysi in the Korinthia region of Greece (GPS coordinates: 37.91672, 22.99402). The theatre occupies the slope of a shallow ravine northeast of the plateau where the Temple of Poseidon stands (Diazoma).

Nearby landmarks include the Temple of Poseidon, which served as the sanctuary’s focal point, and the Classical Stadium where athletic competitions were held. The integrated nature of these structures highlights the theatre’s role not only as an entertainment venue but as an essential component in the religious and cultural activities that took place at the Isthmian Sanctuary.

Historical Context

The initial construction of the Isthmia theatre dates to the second half of the 5th century BCE (before 390 BCE according to Sear), coinciding with the construction of the Classical Temple of Poseidon and the Classical Stadium (Diazoma). This period marked a significant phase of architectural development at the sanctuary, reflecting the growing importance of the Isthmian Games in the Panhellenic festival circuit.

The Isthmian Games themselves were biannual, like those at Nemea, and were crown games where winners received wreaths as prizes. These games included not only athletic competitions but also musical events (Gebhard, “Poseidon will Protect You”). The theatre would have played an important role in these cultural activities, serving as a venue for performances during festival periods.

Historically, the theatre witnessed several major events and transformations. Following the Roman conquest and the destruction of Corinth in 146 BCE, the Isthmian Games were temporarily transferred to Sicyon (Sear 398). When the games returned to the sanctuary in Roman times, the theatre underwent substantial renovation to accommodate these prestigious events. Perhaps the most notable historical event associated with the theatre was Emperor Nero’s participation in the Isthmian Games of 68/69 CE (Diazoma). Several late authors, including Pseudo-Lucian and Philostratus, mention Nero’s victories in these games (Sear 398), highlighting the theatre’s significance in imperial Roman culture and politics.

The cultural importance of the Isthmia theatre is further attested by Pausanias (2.1.7), who described it as “worth seeing” in his tour of Greece written in the 2nd century CE (Sear 398). This reference underscores the theatre’s prominence among the numerous theatrical structures that dotted the ancient Greek landscape.

Architectural Specifications

The following specifications are drawn from Frank Sear’s reference book, Roman Theatres: An Architectural Study (Oxford University Press, 2006), except where otherwise noted.

Location

The theatre is oriented with its cavea facing north, positioned on the slope of a shallow ravine northeast of the Sanctuary of Poseidon (Sear 398).

The theatre lies approximately 80 meters northeast of the Temple of Poseidon on a natural slope that was modified to create the appropriate theatrical space (Wikipedia). This location would have allowed for convenient access from the central sanctuary area while providing suitable terrain for the theatre’s construction. GPS coordinates: 37.91672, 22.99402)

Cavea (seating area)

The cavea underwent several phases of development throughout the theatre’s history. In its earliest Greek form, the cavea was three-sided with a trapezoidal orchestra, measuring approximately 33.5 meters in diameter by the third period of construction (Sear 398). The original seating area was cut into the clay near the bottom of the hill, utilizing the natural slope to support the structure.

Through excavations led by Elizabeth Gebhard and Oscar Broneer in 1959, 1960, and 1967, it was established that the cavea of the 5th century BCE was partly polygonal rather than semicircular (Wikipedia). This discovery revised earlier understandings of the theatre’s original form and highlighted its unique architectural characteristics among early Greek theatres.

In the second Greek period, the seating was arranged in six cunei (wedge-shaped sections), probably constructed with rectangular stone blocks. Earth was packed behind these blocks to form foot-rests for the row above, following a design similar to that found at Eretria and Corinth (Sear 398). Near the end of the 4th century BCE, the theatre was remodeled with an enlarged semicircular seating area, though the absence of seat foundations from this period prevented excavators from finding evidence of stairway restorations (Wikipedia).

During the Roman renovation, the cavea was expanded to exceed a semicircle, reaching a diameter of approximately 72 meters. The slope was made steeper, changing from a ratio of 1:3.20 to 1:2.72. The Roman cavea featured eight rows of stone seats (height 0.34 meters) divided into seven cunei, with the upper seating possibly constructed of wood (Sear 398). There were plans to enlarge the cavea further by building concrete piers around the perimeter, but this project was abandoned, though foundations were laid during the 2nd century CE (Diazoma).

Regarding capacity, Gebhard estimates that approximately 1,550 spectators could fit in the lower level alone, with more room available on the slope above the cavea (Wikipedia). This substantial capacity reflects the theatre’s importance as a performance venue during the Isthmian Games and other religious festivals.

Orchestra (performance space between audience and stage)

The orchestra in the earliest phase was trapezoidal in shape, cut into the clay of the ravine. Two gutter channels (width 0.40 m; depth 0.10-0.20 m) were constructed, with the east branch sloping towards a manhole in the southeast corner that connected to an underground drain (Sear 398). A mud-brick retaining wall was built on the north side of the orchestra.

In the initial construction period, the orchestra consisted of a hollow that served as a performance space surrounded by the seating area for spectators (Wikipedia). This simple arrangement was typical of early Greek theatrical spaces, prioritizing functionality over elaborate architectural features.

In the Roman period, the orchestra was redesigned with a diameter of approximately 17.6 meters. A notable feature of this renovation was the erection of two large Ionic columns in the orchestra near the ends of the stage (Sear 398). These columns stood 7.80 meters high with Ionic capitals and possibly served as supports for massive statues. Archaeological evidence of these columns was later discovered, with twelve vertebrae, both capitals, and part of the foundation built into the walls of the Byzantine Fortress “Examilia” (Diazoma), demonstrating the common practice of repurposing architectural elements from ancient structures in later periods.

Pulpitum (stage)

The stage evolved significantly throughout the theatre’s history. In its first Greek phase, the stage was narrow and may have stood in front of the mud-brick retaining wall at orchestra level. A north-south passage, lined with sun-dried bricks, was cut through the clay bank behind the retaining wall, probably for access to the orchestra through doorway or doorways in the proscaenium. At the north end of this passage, a small staircase led up to what may have been a wooden scene building on top of the clay bank (Sear 398).

During the second Greek period, the stage was made deeper and raised on 12 wooden supports, with access probably provided by ramps. The proscaenium was constructed with 11 openings between support pillars, closed with tourniquets. The entire construction was made of wood and could be dismantled between festival periods (Diazoma), reflecting the periodic nature of performances at the site.

In the third Greek period, a new stage (height c.2.70 m; length 15.17 m; width 2.34 m) was built slightly nearer to the orchestra than the previous one. This stage was supported by 12 wooden posts resting on a stone sill (Sear 398).

The Roman renovation maintained a high and narrow pulpitum rather than adopting the lower, wider stage typical of Roman theatres (Diazoma). A new proscaenium (front of the stage building) of solid masonry was erected on the sill of the old proscaenium (Sear 398). This retention of Greek elements within the Roman renovation suggests a respect for the theatre’s original design and possibly local theatrical traditions.

Scaenae Frons (decorative scene house front)

There were three successive scene buildings throughout the Greek period, all probably of wood. The third measured 15.60 meters in length and 6.03 meters in width, with a north-south passage (width 1.80 meters) running under the middle of the scene building and connecting the proscaenium with the rear of the scene building (Sear 398).

The Roman renovation included the addition of a scaenae frons (decorative backdrop) to the stage building. The scene building was enlarged by the addition of lateral wings which extended to the ends of the parodoi. The central part of the scene building was rebuilt in rubble masonry and the central passage vaulted over. Six large piers were built against the scaenae frons wall, possibly to carry columns or statues (Sear 398).

Although the theatre acquired these characteristically Roman features, it did not undergo a complete conversion to the Roman theatre form as seen at sites like Corinth. There was no attempt to convert it into a fully Roman theatre (Sear 398). Instead, it maintained elements of its Greek design while incorporating Roman architectural elements.

Ornamentation

Limited information exists regarding the theatre’s ornamentation, though the two large Ionic columns in the orchestra represent significant decorative elements. Twelve vertebrae of these columns, both capitals, and part of the foundation were later discovered built into the walls of the Byzantine Fortress “Examilia” (Diazoma), suggesting the reuse of architectural elements in later periods.

The presence of six large piers against the scaenae frons wall indicates potential for decorative elements, possibly including columns or statues, though details of these features remain unclear from the available sources.

Access and Circulation

The theatre featured two parodoi (side entrances) measuring 11.85 meters (west) and 12.20 meters (east) in length. These parodoi ran at an angle of 8° to the line of the proscaenium and sloped down steeply. Long retaining walls were erected along the north side of each parodos (Sear 398).

A north-south passage lined with sun-dried bricks was cut through the clay bank behind the retaining wall, probably to provide access to the orchestra through doorways in the proscaenium. At the north end of this passage, a small staircase led up to what may have been a wooden scene building on top of the clay bank (Sear 398).

In the Roman period, the theatre’s circulation system was modified. The central passage crossing the stage was vaulted over, and domes were constructed to cover the two side entrances (parodoi) (Diazoma). Behind the stage, a large courtyard with wooden colonnades on both sides was created. The east and west sides of this court were crossed by roads connecting the theatre with buildings to the north that have not yet been fully excavated (Diazoma). A porticus post scaenam (quadriporticus) may have been planned behind the scene building, though it is unclear if this was fully realized (Sear 398).

Current Status

The Isthmia theatre presents a challenging case for preservation due to its complex construction history and the nature of its remains. While the site has been excavated and studied, it does not retain the impressive above-ground presence of better-preserved ancient theatres like those at Epidaurus or Delphi. Many of its architectural elements were dismantled in antiquity or repurposed in later structures, as evidenced by the columns found in the Byzantine fortress.

The site is under the protection of the Greek Archaeological Service, though it does not currently hold UNESCO World Heritage status. The Diazoma Association, a Greek non-profit organization dedicated to the research, protection, and promotion of ancient theatres, includes the Isthmia theatre in its catalog of significant theatrical structures requiring attention and conservation efforts (Diazoma).

By permission of the Greek Ministry of Culture and Sports, under the auspices of the American School of Classical Studies at Athens, and with the support of academic institutions like Michigan State University, ongoing archaeological research continues to enhance our understanding of the theatre and its role within the Sanctuary of Poseidon (Michigan State University).

The Michigan State University Excavations at Isthmia conducts an active program of archaeological research, training/education, and publication centered on the ancient Sanctuary of Poseidon in Greece (Michigan State University). 

Renovations

Greek Period

• First Phase (pre-390 BCE): Initial three-sided performance space using natural ravine topography; partly polygonal cavea with trapezoidal orchestra below ground level (Wikipedia, Sear 398, Diazoma); built alongside Classical Temple of Poseidon and Stadium (Diazoma)
• Second Phase (late 4th century BCE): Widened cavea with curved shape and six cunei (Sear 398); deeper wooden stage on supports with 11-opening proscaenium (Diazoma); dismantlable design coordinated with biannual Isthmian Games (Diazoma, American College of Greece)
• Third Phase (later Greek period): Stage rebuilt closer to orchestra, supported by 12 wooden posts on stone sill (Sear 398)

Roman Period

• Initial Roman Renovation (post-146 BCE): Following Roman conquest, games temporarily transferred to Sicyon (Diazoma); steeper, expanded cavea (214° curve) with seven cunei and eight stone seat rows (Sear 398, Diazoma); two Ionic columns added to orchestra; enlarged stage building with lateral wings (Sear 398)
• Neronian Modifications (68/69 CE): Scene building center rebuilt in rubble masonry with vaulted central passage (Diazoma); likely for imperial ceremonies (Sear 398)
• Planned Expansion (2nd century CE): Unfinished attempt during Marcus Aurelius’ reign to extend cavea to ravine top using concrete piers (Sear 398, Diazoma); stage building gained Roman scaenae frons with six large piers (Sear 398)

Archaeological Research

• Early Excavations
  • 1952: Oscar Broneer discovers site and begins University of Chicago excavations (Wikipedia)
  • 1952-1967: Broneer uncovers temple, theatre, dining caves, and stadia (Wikipedia)
  • 1959, 1960, 1967: Theatre-specific excavations reveal classical structure with multiple renovations (Wikipedia)
  • Key discovery: Initial cavea identified as partly polygonal rather than semicircular (Wikipedia)

   Major Publications and Leadership

  • 1973: Elizabeth R. Gebhard publishes “The Theater at Isthmia” (Wikipedia)
  • 1976: Gebhard takes over management of University of Chicago project (Wikipedia)
  • 1987: Timothy E. Gregory succeeds Paul A. Clement as Director (Michigan State University)
  • 2020: Jon M. Frey and Michigan State University assume leadership (Michigan State University)

Bibliography / Resources:

“Ancient Theater of Isthmia.” Diazoma. Diazoma Association, Athens, Greece, 2016-2022, https://diazoma.gr/en/theaters/ancient-theater-isthmia/. Accessed 29 Nov. 2024.

Broneer, Oscar. “Excavations at Isthmia, 1954.” Hesperia, vol. 24, 1955, pp. 110-141.

“Dr Elizabeth Gebhard Lectures on ‘Puzzle Solving’ at the Poseidon Sanctuary at Isthmia.” The American College of Greece, 3 June 2016, www.acg.edu/news-events/news/dr-elizabeth-gebhard-lectures-on-puzzle-solving-at-the-poseidon-sanctuary-at-isthmia/. Accessed 24 Mar. 2025.

Gebhard, Elizabeth R. The Theater at Isthmia. University of Chicago Press, 1973.

“Isthmia (sanctuary).” Wikipedia, Wikimedia Foundation, 6 Nov. 2024, https://en.wikipedia.org/wiki/Isthmia_(sanctuary). Accessed 24 Mar. 2025.

“The Michigan State University Excavations at Isthmia.” Michigan State University, https://msuisthmia.org/. Accessed 24 Mar. 2025.

Sear, Frank. Roman Theatres: An Architectural Study. Oxford University Press, 2006.