OSU Fieldwork at Isthmia

Over the past two decades, The Ohio State University has been involved in numerous archaeological projects in the region of the Korinthia, every summer attracting scholars and students from around the world. Several monographs and many articles have been published about these endeavors, while a few other areas are currently being published or are under study. Although the Excavations at Isthmia is the largest and longest running of these projects, OSU has also been involved in other small-scale excavations as well as several significant surveys. Each of these undertakings requires collaboration with other institutions, numerous archaeologists, and specialists in geology, geomorphology, statistics, map work, museum studies, computers, GIS, botany, faunal analysis, osteology, and architecture. This section will examine some of Ohio State's past and current archaeological projects.

Excavations at Isthmia

(Figure 6.1) The starting gate of the Early Stadium.As discussed in the previous section, Isthmia was a large Panhellenic sanctuary dedicated to the worship of Poseidon. At different times in its history, it was the home of great temples, racetracks, cult caves, theatre, pool, Bath, fortress, houses, and even major defensive works. During Greco-Roman times, its games every two years attracted visitors from across the Greek-speaking world (Figure 6.1). In the Late Roman period, the building material from the site was used to construct the Hexamilion Wall, the defensive fortification that stretched across the Isthmus, defending the Peloponnesos against attack from northern Greece. The complexity of such a history has been corroborated over the past half century through the near-continual fieldwork at the site, beginning in the 1950s, under the sponsorship of the University of Chicago. Yet, despite all the work that has gone on, much of the site still remains unexplored. Most of the athletic buildings, for example, which must have existed in the Classical and Roman periods, have simply not been found. Further excavations are needed to illuminate the history of the site.

Fieldwork at Isthmia is presently under the direction of the University of Chicago and The Ohio State University. The former, under the direction of Elizabeth R. Gebhard, is responsible for the central part of the Sanctuary, while OSU excavations, since 1987 under the direction of Timothy E. Gregory, have focused on the Roman Bath, the Byzantine Fortifications, the West Cemetery, and the East Field. Currently, the Excavations at Isthmia is the largest of OSU's projects, and many areas of the site, including the Byzantine Fortress and the Roman Bath, have been or are currently being published, while other areas are still under study.

The Roman Bath

(Figure 6.2) The Roman Bath.Excavations of the Roman Bath at Isthmia have uncovered an enormous complex with a long and variable history. The Roman Bath was built in the mid-second century AD on the foundation of an earlier Greek pool that dates back to at least the fourth century BC (Figure 6.2). Archaeological remains have shown that the bath continued in use until its abandonment in the late fourth century AD, after which it fell into decay and finally collapsed in the late sixth century. Pottery, walls, hearths, and cement floors suggest activities continued in this area during the Byzantine seventh and eighth centuries.

After it collapsed the Bath was covered by centuries of deposits and only discovered in modern times. By the time the traveler William Leake visited the area in the early 1800s, only one arch on the northern end protruded from the surface to give any clue of the structure that lay buried beneath; that traveler thought the bath was a small fortress connected with the Isthmian wall. It was not until 1954 that the complex was investigated archaeologically. In that year, Oscar Broneer of the University of Chicago placed a small trench at the southern end of the bath, revealing parts of Rooms XI and XIII. From the hypocausts and glass fragments uncovered in those rooms, he correctly identified it as bathing establishment of the Roman period that merited further investigation. Most of this investigation was carried out between 1972 and 1980 by Paul Clement of UCLA. The pace of excavation was amazing. In the first major field season, 1972, Clement's crews uncovered the entire northern third of the bath, clearing Rooms I to V, sometimes to the depth of up to three meters. In only four field seasons, between 1972 and 1978, excavators were able to define the plan of the entire Roman Bath. The Ohio State University became responsible for fieldwork at the bath beginning in 1987. There followed additional small-scale explorations and a major effort to conserve the architecture and especially the monochrome mosaic in Room VI.

Roman Bathing at Isthmia:

(Figure 6.3) Paln for the Roman Bath.Bathing in Roman times was a drawn-out social event, potentially lasting several hours and involving a trip through the complex. The entrance to the Roman Bath at Isthmia was probably either in the north, through Room I or in the south through Room XII (Figure 6.3). After entering the building, the Bather would have proceeded to change in Rooms I, II or VIII. Individuals would then have proceeded to the most decorative Room VI, the famous mosaic room. This was the main gathering hall of the structure and where much conversation and socializing would have taken place. After conversing with friends, the Bather might have gone on to the caldarium (hot room, Rooms XI and XIII), to the tepidarium (warm room, Rooms IX and X), and then to the frigidarium (cold rooms, Rooms III-V), to take a dip in the cool plunge pools. After spending some time there, the Bather might have exited in the same place from which he entered. Alternatively, the Bather might have reversed this order, or spent all of his time in one of the rooms. Unfortunately, we do not know who used the Bath - whether its furnaces were fired only during the festival (every two years) - and whether athletes used the Bath as part of their training and relaxation. Were women allowed to Bathe in the building? Unfortunately there is presently no clear evidence one way or another.

Room VI:

(Figure 6.4) Central panel of the mosaic floor.Room VI is the most prominent and central room of the Roman Bath at Isthmia and the main gathering place for visiting Bathers. Besides being the largest room in the building, it also was the most elaborately decorated, complete with a large monochrome mosaic and a colossal sculptural group on a large base along the west wall. The mosaic, together with the statue base and sculpture fragments, clearly identifies Room VI as the great hall of the Roman Bath complex. The mosaic was monochrome, made up of many small black and white tesserae, tiny stone cubes that were placed together in a variety of designs and patterns. The eastern and western thirds of the mosaic are decorated with geometric patterns and the border of the mosaic is composed of square and rectangular panels containing dolphins, flowers, and crosslets; the large central panels are mirror-images of themselves, depicting Tritons with Nereids on their backs, surrounded by various sea creatures (Figure 6.4). These powerful scenes are known as a "marine thiasos" and is probably connected with the worship of the god Dionysus. This is the largest monochrome mosaic in the eastern Mediterranean, measuring approximately 20 meters by 8 meters.

The Frigidarium:

Rooms III, IV, and V together constitute the complex known as the frigidarium (the cold room). Room III, which was a small hall lined with cut marble slabs and perhaps also decorated with statues and paintings, was the entranceway to the cold Bathing. It led down by three stairs to Rooms IV and V, the cold plunge pools where one would actually be able to get into the water. The floors and walls of these pools were also lined with marble slabs, evident by the setting lines in the cement. The slabs on the wall rose to a height of 1.30 meter, probably the height of the water in the pools; painted floral patterns decorated the plaster wall above this level.

The Tepidaria and Caldaria:

(Figure 6.5) Hypocausts (Room IX)Rooms IX, X, XI, and XIII were all heated spaces, each warmed by one or more furnaces. Beyond the furnaces and under the floor was a sophisticated system called hypocausts. The hypocaust system was made of piers of stacked clay disks that may at first seem puzzling to someone unfamiliar with Roman baths, visible in all these rooms still today (Figure 6.5). The round and square tiles (approximately .30m in diameter) were stacked one-and-a-half meters high on a cement sub-floor and were covered over with mortar, large square tiles, and nicely cut marble slabs, forming the floor of those rooms. Thus, what we see in these rooms today is not the floor, but actually the sub-floor hypocaust area. Furnaces were located to the south of Rooms IX, XI, on the north and south sides of Room XIII, and north of Room X. As the fire blazed underneath, the hypocausts were sufficiently warmed to heat up the entire room above, much like a modern sauna, and the smoke escaped through numerous flues in the wall, providing effective heating for the whole room. Indeed, the furnaces extended also beneath the rectangular pools on the northern and southern ends of Room XIII and the apsidal pool on the south end of Room XI; these areas provided heated water for those who wished to have warm baths. Since furnaces lie directly under pools in Rooms XI and XIII, it is assumed that these were "hot rooms" or caldaria, while Room IX was a "warm room" or tepidarium. Room X might have been a "heat lock," a transitional space between the hot and the cold rooms. The service area of the Bath lay along the southern end of Rooms VIII, IX, XI, and XIII and Room XIV itself, an enclosed area totally invisible from both inside and outside the Bath. From here, slaves would have gathered wood to stoke the furnaces. The height of the hypocausts above the lower floor provided just enough room for children or small adults to crawl beneath the floors and stoke a fire to heat the room.

Water Supply:

The Roman Bath at Isthmia required enormous quantities of fresh water for its use. Indeed, the primary characteristics of Baths in general were the wealth and luxuriousness of their size and decoration, as well as ample supplies of water - an expensive and precious commodity in all periods. Presumably, the water must have been brought into the building under pressure and one or more decorative fountains probably decorated the interior of the Bath. Fortunately, there was an ample supply of water in the vicinity, located several hundred meters to the southwest. Presumably the water was brought to the Bath in one or more (probably above ground) aqueducts, but no trace of these has been found. The water may have been stored in tanks, perhaps even on the roof of the building, and one or more reservoirs discovered on higher ground south of the Bath may also have stored water for it.


Pools and baths depend upon a constant supply of fresh water and thus a sophisticated drainage system is a necessary part of any working bath. The drainage system of the Roman Bath, which was largely explored during the 1976 field season, was well preserved. Horizontal drains, constructed of large rectangular blocks and covered with waterproof cement, were found in Rooms I, III, VI, and IX, all emptying into a vertical drain in the southwest corner of Room II. Two of the drains were purposefully blocked with large stones in Late Antiquity and converted into a tomb; three skeletons were found, probably representing individuals who defended the Hexamilion Wall. In several modern experiments, the drains still worked sufficiently well after 2000 years. The drains in the Roman Baths at Isthmia were kept clear until AD 400 when they became filled with objects such as coins and pottery, both of which are used by archaeologists to date the clogging of the drain.


The entire interior of the Roman Bath at Isthmia was lavishly decorated. The ceiling consisted of barrel vaults, which would have towered majestically above floors covered with marble slabs or mosaics. Although Room VI certainly contained the largest mosaic, other rooms of the bath (I, II, VII. and probably VIII), also had unpatterned mosaics, with tesserae of various colors: white, pale gray, yellow, pink, and orange. Bath walls were adorned with variegated marbles, decorated plasters, and architectural moldings. Excavations also produced a variety capitals, such as those found in Room IX, one with palmette decoration (IA 77-28), the other with dolphin and trident (IA 77-1). Additionally, some sculpture was also recovered, most notably the life-size portrait of Polydeukion (IS 78-12) found just south of the Bath. Statues also would certainly have stood at one or perhaps both ends of Room VI, as evidenced by the several giant statue bases and colossal statue fragments.

The Restoration of the Monochrome Mosaic

(Figure 6.6) Damaged central panel, prior to restoration.The monochrome mosaic in Room VI was unearthed in 1976, in relatively good condition but cracking in several spots and sunk as much as 0.30 meters below the original surface; the unearthing of the mosaic and subsequent exposure to the elements led to further deterioration (Figure 6.6). At the outset, it was obvious that the mosaic would have to be restored if it were to remain for posterity, and indeed Paul Clement initiated this process in 1980; however, full-scale restoration did not really begin for another ten years, this time under the direction of The Ohio State University. In 1990, the Ohio State University in cooperation with the Department of Conservation of the Greek Ministry of Culture, began an expensive and time-consuming conservation process: lifting the mosaic from its current foundation, piecing it back together, and then resetting it in place on a new, stronger concrete foundation. This work was generously supported by the David and Lucille Packard Foundation and the Samuel H. Kress Foundation. There are generally two ways of removing mosaics for restoration: 1) the "sectional" method, which cuts the mosaics into sections and then removes the parts separately; and 2) the "rolling" method, which rolls up the mosaic like a layer of carpet. Because the mosaic at Isthmia was already broken in spots, Isthmia staff opted for the sectional method, cutting the mosaic into rectangular panels (approximately 1.0 m. by 0.70 m.). After the entire mosaic was documented, mapped, and photographed, and the mosaic was washed clean of dirt particles, individual sections were then "chiseled" out, two layers of cloth were glued to the surface of the sections to keep the tesserae in place, and long iron bars were wedged through the mortar underneath the panels and then pried up, removing the panel from the rest of the mosaic.

(Figure 6.7) Central panels restored.Each section lifted from its context was restored, the tesserae scrubbed and cleaned of the ancient mortar. The 148 sections from the mosaic were stored in a shed on the site. Once the whole mosaic had been removed, excavation was conducted below the level of mosaic floor. Besides uncovering a Roman level of fill intended to raise the room to the desired level of the Bath, investigation also revealed further evidences of the Greek pool. More importantly, the ceramics found in the fill below the sealed mosaic floor date the fill (and consequently, the mosaic floor) to the mid-second century. This provides a construction date of about 150-170 AD. Following the excavation of the fill, the area under the mosaic was refilled with the original soil intermixed with modern debris and coins. The seemingly bizarre activity of placing modern material in an excavated context is actually commonplace in archaeological excavations as a way of ensuring that future archaeologists will realize that this area had been excavated. After the pool had been refilled, archaeologists sealed it with a fresh layer of concrete and laid the 148 mosaic panels back in place, an arduous process that took over four years (Figure 6.7).

The Greek Pool

(Figure 6.8) A portion of the Greek Pool.One of the major surprises of the excavations of the Roman Bath was the uncovering of an earlier Greek pool, first discovered when excavations penetrated below level of the Roman construction (Figure 6.8). The pool is at a slightly different orientation from the Roman Bath structure. The construction of the pool dates to the fourth century BC and represents one of the largest Greek bathing facilities known. With a depth of about one meter and walls approximately 100 Greek feet in length (a Greek foot = 0.320 m.), the pool was able to hold 1,275 cubic meters of water, suggesting a sizable feature at the Sanctuary of Poseidon. The Greek pool was lined with a solid waterproof cement with excellent capacities for holding water, and indeed, following excavation, a rain storm left a pool of water that did not seep through the floors and walls; only the 2500 year old drain took the water away.

There were at two phases of construction during the Greek period, the latter dating to the fourth century BC. Excavations revealed an even earlier Greek water device (perhaps an earlier pool) beneath Room III, although little is known about this first phase. When it was excavated, the floor of the Greek pool was covered only with the soil dumped in by the Roman builders, suggesting that the Romans had probably been using the Greek pool, taking advantage of what already existed on the site. They later built the Roman Bath complex directly on the Greek foundation.

The Roman Bath Area today

Fieldwork at the Roman Bath continues today at a slow pace. Excavation has not occurred during the last several seasons. The main thrust of restoring the mosaic is now complete. However, in the last several seasons, minor conservation work has continued, as many loose tesserae still need to be chiseled, cleaned, and placed back into the mosaic. More importantly, during this time the Ohio State University Excavations at Isthmia has been seeking permission from the Greek authorities to construct a roof over the mosaic and to develop an overall conservation plan that will call, not only for protection of the building, but also for its use as a significant cultural center. This is an important step in the preservation of the site since it protects against the heavy winter rains and the constant glare of the summer sun, ensuring that the Mediterranean's largest monochrome mosaic will see many future days, while making the building accessible to visitors with differing interests.

The Roman Bath is today at the point of publication. Although the Bath remains partially unexcavated on the west side, and the area immediately outside the Bath is largely unexplored, the overall plan is sufficiently known that the results can be published. The forthcoming publication will include chapters on various aspects of the Bath: decoration, architecture and drainage, pottery, and lamps. After nearly a half century of archaeological fieldwork, the life of this magnificent building soon will be made available for everyone's enjoyment.

The East Field

(Figure 6.9) East Field walls (Type 3)The enigmatic East Field lies fifty meters east of the Temple of Poseidon and south of the theater. It is an area that is only partly excavated that demands future analysis and publication. Excavation in this area revealed a series of multiperiod, small structures, with poorly constructed walls set at various orientations (Figure 6.9). That the walls probably represent houses or living quarters is suggested by the water facilities and food preparation areas. It is especially surprising that these small buildings would be located right at the entrance to the Sanctuary. Although most of the archaeological remains are from third century AD in date, the site was obviously used for a long period of time, which party explains its intricacy. Indeed, the East Field is an excellent example of how complex archaeological excavation and analysis can be. Conclusions regarding the purpose and history of the area will only come with further study of the artifacts and excavation records, and for this reason, the East Field will continue to play an important part of future field seasons at Isthmia.

The Hexamilion and the Byzantine Fortress

A massive fortification wall runs along the northern side of the Roman Bath. This fortified wall is known as the Hexamilion ("6-mile") Wall, because it runs nearly six miles across the entire Isthmus of Korinth, from the Korinthian to the Saronic Gulf, defending the Peloponnessos (southern Greece) from invasions coming from the North. Because this area of the Isthmus is very narrow, several attempts to construct a wall here were made before the Byzantine period. However, only the fortification of the Isthmus in the fifth century AD, during the reign of Theodosius II (AD 408-450), was successfully achieved. This wall was constructed of large ashlar (squared) masonry blocks, mortar, and rubble, and it was intended to prevent Visigoth invaders from penetrating the area. Many parts of it still survive today.

The Byzantine Fortress, which lies 150 meters to the east of the Roman Bath and projects southward from the Hexamilion Wall, also dates to the fifth century. The Fortress incorporated a Roman monumental arch into its Northeast Gate, and this would have marked the grand entrance to the Sanctuary and the Fortress, and perhaps the Peloponnesos as a whole. Excavation in the northern areas of the Fortress uncovered many graves, sometimes containing several burials. Although archaeologists expected that the individuals buried in the Fortress would all have been soldiers, many were women and children -- suggesting that families lived within the Fortress and that life continued in the Fortress even in times of peace. Like the Hexamilion Wall, the Fortress was certainly used and refurbished after the fifth century, during the later Byzantine, Frankish, and Venetian periods, at least until the 17th century AD.

(Figure 6.10) Spolia Study.The Hexamilion and the Fortress are continued points of interest and study for OSU Excavations at Isthmia. Recent work has centered on recording the numerous spolia (reused blocks) used as construction material in the Wall and Fortress (Figure 6.10). During the fifth century AD, when the fortifications were being constructed, the builders made use of the ready supply of cut stone and marble that had originally been part of temple, Bath, theatre, and athletic structures, but had since fallen into disuse. The study of the spolia has focused on locating, identifying, and recording blocks that originated from the structures at Isthmia. This project is ongoing and expected to continue in the immediate future.