The OSU Excavations at Isthmia - 1992 Preliminary Report

Fieldwork at Isthmia sponsored by The Ohio State University took place from January to September, with most activity taking place between 28 June and 8 August. Thanks are due to Mrs. F. Pachygianni and Mrs. Z. Aslamatizdou of the Fourth Ephoreia of Classical Antiquities and to Mr. Ioannis Daglis of the Department of Conservation of the Ministry of Culture, for unfailing support and encouragement.

Our primary focus this year was the continued conservation of the large monochrome mosaic in the Roman Bath, discovered in 1976 and lifted in 1990. In 1991 the area under the mosaic had been filled with soil up to a level 0.50 m. below the original surface of the mosaic; a layer of stones 0.30 m. thick was placed above this. Conservation of the mosaic in 1992 began in January with further leveling of the stones and the construction of wooden forms, dividing the bedding for the mosaic into rectangles roughly 3 m. (north-south) by 2 m. (east-west), designed to allow the restored surface to move slightly as a result of earthquake or subsidence without breaking. In April of 1992 a layer of concrete ca. 0. 15 m. thick was poured into the forms over the stones in order to form a firm foundation upon which the mosaic could be re-laid. The concrete was then allowed cure and dry thoroughly for three months.

Relaying of the mosaic began on 14 July and ended on 30 July; this work was directly supervised by Ioannis Daglis, with the assistance of Vasilis Marinos of the Fourth Ephoreia of Classical Antiquities. Conservation began with the preparation of a mortar mixture that precisely matched the original mortar bedding for the mosaic, both in color and in texture. This process required the preparation of many mortar samples, with varying proportions of the different ingredients; these samples were allowed to dry and they were compared with the original mortar still in situ in the Bath.

Once the appropriate mortar mixture was determined, Mr. Daglis began the process of re-laying the mosaic panels. Considerable care was necessary at the beginning of this process, in order to replace the panels in precisely their original position and to avoid, as much as possible, signs of modern conservation. The large size of the mosaic (ca. 7m. x 20m.) meant that any mistake committed at the outset would be multiplied many times over by the end of the process, so work at the beginning was carefully and slowly executed, based upon lines set up to insure that the panels and the lines within them would be properly aligned. Each day a small amount of mortar (appropriate for laying 3-4 panels) was prepared in a cement mixer; this was then spread out where the panels would be laid. The individual sections of mosaic were then removed from the boards on which they had been stored and then laid, in their original location, with the two layers of cloth still holding the tesserae intact. The mortar was then allowed to dry slowly by wetting the surface periodically to avoid cracking as a result of uneven drying. When the mortar had dried sufficiently, the covering cloth was removed, the surface was cleaned, and preparations were made to fill the spaces between the mosaic panels with a thin line of tesserae, laid in place by hand.

Relaying of the mosaic panels began at the western end of the room and proceeded toward the east. Each row of panels contained seven individual pieces, and by the end of the season three rows, for a total of twenty-one panels, had been re-laid. This work is naturally painstaking and slow and great care had to be exercised in the early stages of the undertaking. We hope that the task of relaying the whole mosaic may be completed during the 1993 season.

During the 1991 season we had noted that road construction carried out by land developers was threatening the safety of the underground Northwest Reservoir and its associated water lines, excavated by Oscar Broneer and published by him in Isthmia II. Early in the 1992 season we noticed that the ancient vertical water shaft leading down into this system had been filled with debris, apparently at the time the roadway was created. With the permission of the ephoreia we cleaned out the manhole and the water system, down to a depth of 6.5m. below the modem surface. We also shored up various places in the water system where the waterproof cement had fallen away and we placed a large cement cap, reinforced with iron, at the top of the manhole.

Further fieldwork was carried out in the area of the Roman Bath, where we cleaned out several trenches excavated in previous years. Thus, we examined the foundations of the east wall of the Bath, excavated in 1978, and we found that the stone and rubble foundations there go down ca. 1.4m. below floor level in the Bath. To the east of this wall there was a structure, ca. 2m. north-south and at least 1.3m. east-west, whose floor and sides are made of tiles simply set in the soil. This structure, which is very similar to another discovered by Oscar Broneer north of the Temple of Poseidon, was probably simply a surface for the mixing and preparation of clay, presumably used in the construction or maintenance of the Bath and perhaps in the manufacture of tiles placed on the building.

In Room IX, excavation in 1977 and 1978 revealed a cement floor on which the hypocausts of the Roman Bath had been placed. Later investigation showed that this cement surface was the floor of the Greek-period pool. This floor had been cut by two long straight cuttings, one running nearly north-south near the west side of the room, the other running east-west between the springings for the apse at the south end. In 1992 we looked again at these cuttings, which probably represent foundations for walls that no longer exist in the Bath. Investigation of the north-south cutting revealed no trace of special foundations, but merely the packing that was encountered elsewhere under the floor of the Greek pool. One may therefore suggest that there had been no substantial wall along this line, but perhaps some feature associated with the Greek Bath. The east-west cutting, however, was filled with foundations made of tiles and mortar, certainly of Roman date, presumably to support a wall no longer extant, from a phase of the Roman Bath earlier than the present arrangement.

In cleaning a trench excavated in 1976 in the southwest corner of Room XIII, we rediscovered a furnace that heated the pool on the southern end of the room. This was remarkably well preserved and it has features that are not represented in the other five furnaces previously studied.

South of the Bath we investigated an area excavated in 1978 and 1980 and described as the South Lamp Deposit. Work this year allowed greater knowledge of the area, and provided evidence of two stratigraphic horizons, the earlier assignable to the original Roman Bath phase in the second century after Christ and the second phase-in which the lamps were previously found- associated with the abandonment of the Bath around AD 400. Also, to the south of the Bath we cleaned a trench excavated in 1972. Close stratigraphic investigation provided evidence of ground levels and construction assignable to the Greek period, above which there was massive leveling in Roman times.

In addition to these investigations, we continued study of the architecture and finds excavated in previous years, especially in the area of the Roman Bath. Progress toward publication of this important monument is well under way, under the supervision of Jeanne Marty (University of North Carolina at Asheville), Fikret Yegul (University of California at Santa Barbara), and Timothy E. Gregory (The Ohio State University).

Jeanne Marty spent much of the summer at Isthmia, working on the amphoras found in Room IX and the pottery discovered under the mosaic in Room VI, lifted in 1990. Her detailed studies allow a precise date for the original construction of the mosaic and provide important information about the abandonment and ultimate destruction of the Bath. She prepared detailed descriptions of all the inventoried Roman pottery excavated in 1990-91 and coordinated this information with the stratigraphic record. Fikret Yegul completed his preliminary survey of the architecture of the Roman Bath and he is ready to write the full-scale study of the Bath for ultimate publication. Both Professor Marty and Professor Yegul presented reports on their investigations at the annual meeting of the Archaeological Institute of America in New Orleans in December.

Timothy E. Gregory
September, 1992