The State of Preservation of the Byzantine Mosaics of the Saint Gabriel Monastery of Qartamin, Tur Abdin (South-West Turkey)

October 10^th–14^th, 2006

[1] The goal of this mission, conducted over five days in October 2006, was to evaluate the state of preservation of the Byzantine mosaics adorning the sanctuary of the church of Saint Gabriel Monastery in Tur Abdin, and to propose solutions for the mosaics’ long-term safeguard and maintenance. Organized by Alain Desreumaux, researcher at the CNRS (Workshop on Ancient Semitic Studies at the Collège de France’s Institute of Semitic Studies: Eastern Mediterranean UMR) and by Sébastien de Courtois, doctoral student at the EHESS, the mission was completed thanks only to the support of the Ministry of Foreign Affairs, and especially of Michel Pierre, who generously covered all transportation costs.

Location

[2] The Monastery of Saint Gabriel, or Mar Gabriel, is located in the region called Tur Abdin (in Syriac, “Mountain of the Servants”), a mountain range in southeast Turkey that overlooks the Mesopotamian plain to the southeast of Diyarbekir. Southeast of Midyat, the monastery is located 5 kilometers from the village of Qartamin, 60 kilometers from the Syrian, and 90 miles from the Iraqi border. At present, the monastery belongs to the Syriac Orthodox Church, and wields special spiritual influence in Tur Abdin thanks to the presence of Archbishop Mor Timotheos Samuel Aktas, the diocesan bishop who resides there.

History

[3] At the heart of Tur Abdin history, the Mar Gabriel Monastery has long been a center of Christianity and Syriac culture in the Middle East. With its monuments and manuscripts, with its many illustrious ascetic saints, monks, bishops, scribes and writers, Tur Abdin has figured prominently in Syrian and Mesopotamian history from the 3^rd century to the present.

[4] The founding of Mar Gabriel likely dates to when Persians murdered Bishop Karpos during a raid on Roman Nisibe in the middle of the fourth century. A Syriac manuscript most probably dating from the thirteenth century (British Museum manuscript, Add. 17265, which is completed by Sachau manuscript 221 of Berlin’s Staatsbibliothek, dated to the seventeenth century) explains the origins of the monastery founded in 397 A.D. by Samuel, Karpos’ spiritual son and a native of Mardin. One of his disciples, Simeon, succeeded him in 408; Simeon had buildings erected and transformed the hermit’s retreat into a spiritual hub sheltering hundreds of monks. Because of its strategic location on the Roman Empire’s eastern frontier, vast construction was undertaken, first under Emperor Arcadius, then under Theodosius II. But it was only Emperor Anastasius’ generosity that allowed the monks to build a large church, finally completed in 512. As the British Museum’s manuscript tells us, Anastasius sent the monks not just gold, but also skilled specialized workers-builders, goldsmiths, sculptors, painters and mosaicists credited with the sanctuary’s mosaic.

[5] In the nineteenth and beginning of the twentieth centuries, several European travelers visited the monastery: H. Pognon in 1899, C. Preusser in 1909, Miss G. Bell in 1909 and 1911. Then, from 1918 to 1954, Tur Abdin became a military zone closed to tourism. In 1954, J. Leroy, researcher at the CNRS, was the first European allowed to see the monastery again. These visitors left descriptions that provide useful testimony on the state of the mosaics’ preservation.

[6] Gertrude Lowthian Bell, who visited the monastery on two separate occasions, took photographs and compiled a map of the buildings, which she published along with two drawings of the ceiling’s mosaics. In 1958, Abbot Jules Leroy briefly mentioned two mosaics he had seen in 1954: “The first (published in Preusser, 1911) shows geometric designs with borders containing aces and spades”. Concerning the second mosaic, he wrote, “one can make out... a cross surrounded by vines. According to [G. Bell in Van Berchem and] Strzygowski, Amida, [1910,] p. 272, this is the oldest example of wall mosaic in Mesopotamia.” Though the mosaic in question is the same that decorates the barrel vaulted ceiling. After each having stayed at the monastery in 1972, Ernest J. W. Hawkins and Marlia C. Mundell conducted further study on the mosaics, and published their findings in Dumbarton Oaks Papers, together with a fine photographic illustration (DOP, 27, 1973, pp. 279-296, 49 fig.).

Description of the Decor

[7] The mosaics in question adorn one room of the main church, situated in the eastern section of the monastery. This space-called “presbyterium” by G. Bell and “sanctuary” by E. Hawkins and M. Mundell-forms the church’s choir, and is partially occupied by a modern altar affixed to the floor. The room measures 4.33 X 5.83 meters; at its center, the barrel vault rises to 5.36 meters.

[8] The description found in the British Museum’s thirteenth-century manuscript states, “The sanctuary’s floor is covered with mosaics of white, black, yellow, purple and maroon marble, with various figures. Its circular walls are covered by marble slabs, and overhead, on the vaulted ceiling, there are mosaics of golden cubes.”

The Pavement

[9] G. Bell mentioned that the pavement was decorated with polychromatic marble, of which J. Leroy offered a brief description upon which E. Hawkins and M. Mundell further elaborated, also presenting three photographs: “The floor of the sanctuary is paved with opus sectile of black, red, and white marbles. A rectangular panel fills the west doorway (fig. 49). The main floor has a rectangular design with a border around the walls and a circular centerpiece with a spiraling pattern around a small grey and white variegated marble disc (32 cm. in diameter), now partly covered by the step in front of the modern altar (figs. 47, 48).”

[10] Covering a surface of about 25.25 m², the flooring is trichromatic opus sectile (black, white, red). Along the checkerboard walls (whose squares are decorated with alternating hourglasses and florets with two spear-shaped petals each), the flooring’s bordering zone is delimited towards the center by a row of white triangles on a black background. The central part of the floor mosaic is adorned with a grid of rows of adjacent squares, which form large quadrangles occupied in turn by four white squares around further black or red squares, all of which are decorated with a four-petal floret of contrasting colors. At the center of this composition, there is a large circle decorated with a “triangle shield” with a double border-one border on a white background being decorated with alternating black beads and black squares and inscribed with a white square; the other border being decorated with alternating black/red and white squares marked with florets of contrasting colors. The center of the shield is marked with a marble disk bordered by a line of red and black triangles.

First Descriptions of the Wall Mosaics

[11] Of the wall mosaics on the vaulted ceiling and lunettes, of which about 45 m² are preserved, G. Bell left precise descriptions: “Of the presbyterium mosaic a precious fragment remains. The barrel vault is covered with a spreading vine, the spirals of which encircle leaves and bunches of grapes (Fig. 21 [drawing from a photograph]) … At each of the four corners, the vine springs from a double handled vase. The body of the vase is divided into two zones by a narrow band; in the lower zone a geometric design springs up from the pointed base. In the centre of the vine, at the top of the vault, there is a rayed crux gemmata enclosed in a circle (Fig. 22 [drawing of the motif]). The vault is bordered by three bands of ornament. The first is a forked pattern worked in three colours; the second a row of hollow 8-pointed stars with a white dot in every point and an ivy leaf in the hollow centre; the third a series of rhomboids, separated from each other by a cross band of three jewels, the whole closely resembling the jewelled bands which occur in Byzantine mosaics of the 6^th century. On the S. wall of the chamber, under the vault, there are fragments of mosaic in which it is possible to make out a small domed tabernacle, the dome carried on two pairs of columns. On the N. wall also there are traces of mosaic, and upon the floor there is a pavement of different coloured marbles. The mosaic on the vault is carried out in red, a pale greenish blue, and white, upon a gold ground… The execution of the vine is fine and delicate in detail, and the realistic treatment is unlike mosaics of the Moslem period.”

[12] This description was further elaborated upon by M.C. Mundell, who was able closely to examine part of the mosaic during her stay at the monastery in August 1972. The stylistic analysis that she gave was accompanied by many photographs of details, which are especially helpful for comparisons as we document of the decor’s present state of preservation.

The Ceiling in 2006

[13] The ceiling presents a decor of vine leaves springing from four canthari vases set in the corners. To accentuate the effect of height, the vines narrow towards the center of the ceiling, which is marked by a radiating crux gemmata drawn onto a starry background, inside a circle made of a row of trisected calices set alternately top to bottom (diam. 1.40 m). In smaller medallions, two other crosses standing on steps face each other on the vaulted ceiling’s spring: one is situated over the west door and is bordered by a guilloche (diam. 59 cm); the other, less complete, is located over the east apse and is bordered by a two-stranded braid (diam. 66 cm). The field is limited by three borders (width: 82 cm): these are, from the inside outwards, a line of nesting chevrons; a strip of eight-pointed stars (each point accented with a little circle) decorated with circles marked with a heart-shaped leaf; and finally a gem-studded line with alternating large and small squares on edge.

[14] Less complete, the southern and northern lunettes present figurative decorations: to the south, framed by two trees (cypresses?), a domed tabernacle supported by columns shelters an altar (?) with two chalices, and oil-lamps hung on each side of the tabernacle; to the north, the decoration, in a ruinous state, seems to have been similar, though only the two side trees and the tabernacle’s dome remain. Made of glass tesserae, a Greek inscription is still partially preserved under the tabernacle of the south lunette. This inscription, studied by C. Mango (DOP, 27, 1973, p. 296), likely gave the sponsors’, or perhaps the mosaicists’ signature.

[15] The backgrounds’ tesserae have gold leaf. In the lunettes, these tesserae are set in regular horizontal lines that are widely spaced, and their surface is tilted slightly down. Jutting out in this way, these tesserae’s reflections are more fetching, catching the light better. The lines’ wide spacing also allowed for savings on tesserae.

Identification of Other Decoration

[16] During our brief mission, only the choir’s decor could be studied, though the monastery also possesses vestiges of other mosaics. According to G. Bell, “Local tradition insists that the vault of the nave was once covered with mosaics like the vault of the presbyterium; possibly a careful examination of the brickwork might yield some evidence as to the truth of this tale.” E. Hawkins and M. Mandel also mentioned the presence of a destroyed mosaic in the choir’ small apse: “The shallow apse bears traces of destroyed mosaic decoration… All the mosaic in the shallow apse recess has been lost, but an irregular area of setting-bed (1.15 m. x 0.75 m.) bearing traces of the frescoes design is exposed on the north side of the original window opening and it is possible that more extends around to the other side underneath comparatively modern renderings. The design on the setting-bed is not immediately apparent thought it seems to be a foliate decoration. Four years ago, as a security precaution, the apse window was almost entirely blocked up…” In a space situated further to the north, Hawkins and Mandel made the following observation: “On the south, east, and north walls of the ‘tomb chamber’ chapel to the north of the northern compartment of the sanctuary, there are areas of the characteristic intermediate rendering for mosaics which bears a rough herringbone pattern of incised lines. This plaster is similar to that which can be seen in some places where mosaic has been lost in the sanctuary (fig. 20), and it is reasonable to suppose that this chamber was decorated with mosaic at the same time as the sanctuary.”

State of Preservation

[17] Already in 1909, Miss Bell noticed that “the vault is much blackened by smoke; if it were cleaned every detail would be visible.” This remark was echoed a half-century later by Abbot Leroy: “The ceiling’s mosaic is difficult to see because of the filth.” Ten years later, in 1968, when he alerted the scientific community to “The present state of Christian monuments in southeast Turkey (Tur Abdin and surroundings)” (CRAI, 1968, p. 483), this same Abbot Leroy painted a sad picture of the mosaics’ condition: the painting in the two lunettes were “destroyed”, he wrote, and “wide sections [of the ceiling] are in danger of immediate collapse”.

[18] But E. Hawkins, who conducted precise observations in November 1972, gave a more detailed description of the mosaics’ state of preservation, also analyzing the remains of ancient mortar. To further his examination, Hawkins mentioned that he had been able to perform a limited cleaning: “The mosaics…cover the vault and lateral lunettes... The lower halves of the walls are now bare, except for some relatively recent wall paintings… The colors of the tesserae are overcast, in some places totally obscured, by thin deposits of lime and soot which give to the whole a light gray or blackened appearance... The deposits on the mosaics were probably created by lime, carried down by rain water from the masonry above, combining with soot from the smoke of frequent fires below. Around its lower parts the mosaic has been partly obscured by splashes and smears of later rough renderings of the walls below… Most of the mosaic of the vault survives, but there are several losses, notably to the west of the center and along the lower part on the west, and to the east behind the top of the modern altar. In the south lunette most of the lower and middle parts of the mosaic has fallen. The greater part of the north lunette mosaic has been lost and of what remains much is in imminent danger of collapse. Other areas where further falls could occur are at the left side of the south lunette and near the center of the vault.”

[19] Hawkins described the mosaic’s mortar setting: “As might be expected over a brick vault, there are three renderings of lime plaster; the first roughly finished, the intermediate keyed with the point of a sharp tool with lines in a broad herringbone pattern for the reception of the setting-bed...”

[20] Concerned that certain parts of the mosaics were in danger of collapsing, Hawkins made sure to stress that “Adequate scaffolding, time, and skilled workmanship will be necessary if this is to be averted. There is indeed an urgent need for steps to be taken to save this unique decoration.” (DOP, 1973, p. 283).

[21] Despite his warnings, no serious conservation work seems to have been undertaken until 1997. At that time, the whole interior of the church was “restored”, the walls were cleaned and all traces of the ancient coating was removed. The stones were bared and repointed with white cement mortar. This also seems to have been when the gaps in the mosaics of the vault’s spring were plugged with beige mortar, underlining the vault’s lower section. A comparison of the present state of preservation with the photographs Hawkins and Mundell included in their article reveals that tesserae have disappeared in places, especially in the southern lunette’s inscription. The damage probably occurred in the course of this restoration work.

[22] More recently, in 2001 or 2002, the region’s governor called in a team of Italian restorers who were working on mosaics found during emergency excavations conducted because of the construction of a dam on the Euphrates, which flooded part of the ancient city of Zeugma. This team’s work lasted two days, and consisted of gluing a layer of gauze to the mosaic to maintain the most weakened sections of the ceiling and lunettes. This gauze is still in place.

State of Preservation in 2006

[23] We are faced with architecture that was entirely renovated without concern for the materials used in the fifth century. The mortars used in ancient times were made up of a lime binder with a mineral mixture (sand, terra cotta, gravel) which let water vapor through. Since it was not hard, it possessed a certain elasticity that allowed it to give without breaking. This is not the case with the modern cement mortars, waterproof and very hard, that were set in place in the twentieth century. Overly hard compared to the ancient materials, they are already detaching.

[24] Therefore, in years to come, we can expect many problems with the architecture (fissures, buckling) which will risk altering the buildings and their decorated parts. This deterioration may have a direct influence on the mosaics’ preservation, since these have been weakened by the mortar’s failure to stick to the walls.

[25] It is regrettable that the restoration work done thus far was conducted without archeological input. This is particularly sad given G. Bell’s photograph showing vestiges of wall paintings, and also Hawkins and Mundell’s examination of the vestiges of mortar that still bore traces of the tesserae lost in other parts of the monastery.

The Opus Sectile

[26] In the very irregular opus sectile flooring, ancient restorations are still visible. These restorations were carried out using grey cement and scattered marble fragments. Though the marble pieces remain in place, several parts have cracks that show the ancient mortar. The floor is normally covered with carpets which have also served to protect it.

The Mosaic

[27] On the mosaic of the barrel vault and lunettes, which was noted in Miss Bell’s first descriptions, a blackish layer has formed on the tesserae’s surface. This layer is composed of chalky concretions, dust and the black smoke rising from candles and incense used in religious ceremonies, but also resulting from general sootiness, even if it seems that at some unknown date, the decor may have been dusted off. We were able to locate the part cleaned by Hawkins in 1972.

[28] However, our examination brought to light graver damage, very worrisome unless action is taken quickly. In many places, the stone and brick masonry has detached from the first layer of gross mortar. This has taken place both in the north lunettes and on the ceiling. This detachment may cause large chunks of the mosaic to fall, particularly in light of the region’s vulnerability to seismic activity and aftershocks. The Italian team recently called in reinforced many of the detached parts, but this can only be a stop-gap measure until true restoration work can be undertaken.

[29] In the south lunette, the lower section has many lacunae, and is plugged with the grey cement mortar seen already in the photographs Hawkins and Mundell took in 1972. This cracked mortar no longer sticks to the wall. In the center of the pictured tabernacle, an older crack was filled with glazed blue ceramic elements (already visible in 1972). It was on this lunette that we located Hawkins’ cleaning test. In comparison with the 1972 photograph, the Greek inscription under the tabernacle has lost several tesserae, probably when the mortar was repointed in 1997.

[30] By comparison with the earliest illustrations, one can see that the north lunette is much more damaged, and a large section of the west side has detached, which is already visible in the single photograph that we possess of the ceiling, taken in 1911. The cracks have been plugged with the same sort of grey cement mortar. However, though the mosaic seems to have shifted only slightly since Hawkins’ stay, all of the mosaics contained in this lunette are in utter decay.

[31] The ceiling also shows cracks: one large crack above the doorway leading in from the central nave, on the western arch, already visible in G. Bell’s photograph; another large crack above the apse and behind the modern altar -this crack was plugged, probably in 1997, with a beige mortar similar to the one that borders the vault’s spring-; besides those, there are numerous smaller cracks, which are old and sooty. Our examination of the vault showed that even if the mortar is barely sticking to the stone, the tesserae are at least satisfactorily adhering to their mortar.

[32] Over the course of our stay, besides the attentive examination of the remains, we were also able to conduct a few cleaning tests on the mosaics of the south lunette, and at the bottom of the vault in the northeast corner.

[33] The entirety of the decor is composed of colored, opaque glass tesserae (dark blue with nuances of light blue, green, red, brown and black), of translucent glass tesserae with a gold and silver backing, of tesserae of white, pink or grayish limestone (or marble? “Pink marble” according to M. C. Mundell). As G. Bell, E. Hawkins and M. Mundell stressed, a gentle cleaning would certainly sharpen the palette and help identify the materials used.

[34] The tesserae are irregular in shape, measuring from about 0.8 to 1 cm along their edge. The tesserae with silver leaf are slightly smaller than the others. Several motifs are rendered by plaques with specific forms (circles, droplets, etc.)

[35] Our observations, however limited, revealed that the limestone, colored glass tesserae, and gold-leafed tesserae are in good condition. Those with silver leaf are less well preserved since the metal at the edges of the tesserae has oxidized (silver oxide). No exfoliation of the glass was noted.

[36] The joints are very sooty, particularly since in this type of wall mosaic, the joints are deeply recessed, which increases chances for dirt deposit.

[37] On the ceiling, we noted the presence of metal clamps stuck into the mosaic, flush with the tesserae’s surface. These hooks reinforce the mortar’s hold on the wall. Because of the general sootiness and our limited time, we were unable to check the regularity of their placement. A list will have to be drawn up, and a more detailed study will need to be conducted of the metal’s state of preservation. Depending on the results, it may be necessary to replace them.

[38] On the ceiling’s western spring, a large hole is visible in the interior of the structure, in the mosaic and its mortars as well as in the wall itself, but a corresponding hole was not found on the ceiling’s exterior. It is most probably the opening for a conduit whose function we were unable to ascertain. The mosaic and its mortar incline slightly into the conduit, proof that the conduit already existed when the mosaics were being laid.

[39] Moreover, we also observed various hooks from which light fixtures have been hung over the centuries. The insertion of these hooks broke numerous holes into the mosaic.

Cleaning

[40] During the October 2006 mission, we conducted two cleaning tests: the first on the tree pictured on the left side of the south lunette (tesserae of colored glass and with gold-leaf), the second at the bottom of the ceiling, in the northeast corner (tesserae with gold leaf and silver leaf, glass tesserae and limestone tesserae). These tests, which were conducted mechanically (with scalpels) revealed a good overall preservation of the tesserae, except for the silver leaf tesserae.