The Monastery of St Moses, Syria: The Buildings

Posted: September 15, 2014 - 12:04 , by Robert Mason
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The main monastery buildings at Deir Mar Musa, Syria, from the South., the same view as the reconstructions in the blog.

The monastery of Deir Mar Musa in its heyday included hermitages spread around the landscape, but as today, the focus of the complex would have been the buildings, especially the chapel, home to the important frescos. The archaeology of standing buildings requires looking at walls to see how they are made, and how they relate to each other. One structure may clearly be seen as one that came first, with later structures abutting on to it. Different phases may be made of different materials, or the same material worked in a different way. At Deir Mar Musa the stones themselves provide evidence in their size and form, and how they were shaped. Once distinct structures are recognised within the complex, they may fit floor patterns of recognised building types that provide a chronology, while sometimes details of door, window, or other attributes may have a chronological association. In an ideal situation inscriptions with dates may be associated with each phase. In this way it is possible to create a history of a complex of buildings, albeit at times a hypothetical one! Eventually a plan like that below will be created, but a two-dimensional representation cannot really describe a three dimensional structure adequately, so reconstruction drawings are often helpful. The reconstruction drawings in this blog are based on the plan.


Phase One: Roman?

There seem to be two structures upon which all the others are built around at Deir Mar Musa. This architecture comprises courses of large stone blocks, typically about 50-60 cm high, about 80 cm wide, and 50 cm thick, although larger and smaller stones are found, all quite well-dressed with a hammer. Two structures on the site have several courses of these blocks, with the stones keyed into the bedrock of the site. The large blocks rise to a height of one storey in the south building and two in the north (for the north building see below). An opening articulated by large blocks in the south wall of the southern structure is almost certainly the original doorway. It is about 1 m high by 60 cm wide, and has sockets for the door and bolt. The doorway is about 150 cm from the base of the wall, and when it was built there would have been a precipitate drop to the valley (the present floor has been built up later). This means that this door would be very inaccessible. This door, the ground-plan, and the large blocks would be suggestive of a Roman watchtower. 

Large blocks require organisation and cranes. Such things are not unique to the Roman period, but in later periods such large blocks only became popular again when developments in trebuchet design made large blocks in castle walls desirable in the 12th century. The simplest way to build with stone is to make a block large enough for one man to carry it. Hence it is logical to hypothesize that only the Romans would be so deliberate as to drag a crane out to the desert to make a building. Roman watchtowers are widespread on the borders of the Empire, and were designed to be visible to each other, so that they could signal. The towers tended to be inaccessible, as this one would have been with a small door high up over a cliff face, and are typically of this plan. The position of this tower would have been perfect for observing one of the main roads between Palmyra/Tadmor and Damascus, which could be the main route an invading army from the East would make. The monastery of Sergius and Bacchus at Dayr al-Nasrani in Jordan is built around a watchtower under similar circumstances.

The now blocked entrance to the suggested Roman watchtower,  the first building at Deir Mar Musa.


Phase Two: The Monastic Foundation

I think the second structure made of large blocks, the northerly of these two buildings, is later. The original watchtower, of which there are examples of towers elsewhere in Greater Syria preserved to a height of six stories, would have been vulnerable to earthquakes, which are common here (see below). So the north building may have been built using blocks from the collapsed Roman watchtower. The present entrance in the north structure is later, comprising a small low door which might be appropriate but the inner archway has a pointed arch and is probably mediaeval. Extensive remodeling has obscured any more likely doorway, although there is a possible gap in the larger stones on the western wall.


Similarly proportioned towers often seem to have doors in the middle of the long side. These "similar" towers are actually often the foundation buildings of monasteries. Defensive towers were an important aspect of monastic foundations of the early Byzantine period and are fairly common on Syrian monasteries. They would often be the first buildings in the monastery, in order to provide shelter for the monks, which would be particularly appropriate here. These are not meant to be tall watchtowers, just strongly built and tall enough so that it is difficult for unwelcome visitors to get inside. The large blocks go to a height of two stories, and the original building was probably no higher until renovations in the later mediaeval period.

The west wall of the main buildings showing several phases of construction. The north building using large blocks is to the left (note the red arrows showing the line where the original building is abutted by a later structure).


Phase Three: The Monastery Chapel

The chapel is not built in one phase, but has several types of stonework in it. The core of the building, including the half piers, the west wall of the nave, and the inner shell of the apse, are badly ordered and comprise some very large stones with smaller stones fitted around them, probably re-used from the Roman towers. This core masonry seems like the work of monks, rather than masons, while the rest of the chapel is obviously the work of a team of highly skilled masonsThis combination would be odd if the building was built in one project. If one considers the plan, this core masonry actually forms the outline of what is considered the most typical plan of monastic churches in the Holy Land by scholar Yadin Hirschfeld. The most reliably dated examples are late 4th or 5th century. There seem to be two main ways of constructing a church of this nature, one with a pitched roof (common in northern Syria), the other with a flat stone roof supported by transverse arches (common in Jordan, Palestine, and Israel), but these parts of the hypothesized chapel are entirely missing. For now I have reconstructed the church with a pitched roof. Typically the better preserved examples, for example at masada in Israel, have a window in the apse.

In comparable monasteries, the church is placed on the north side of the complex, with a courtyard on its southern side to provide space for the community to congregate, a function of particular importance in laura with their infrequent assemblies. The proposed monastery-type church actually provides a far more appropriately sized courtyard for this function at Deir Mar Musa. Typically, the door to a church of this nature would be at the western end, or on the south wall towards the western end, where it is intended to let in light to the church.

Then Br. Jihad and Br. Boutros discussing scripture, the wall behind Br. Jihad dates to the original chapel building.
Phase Four: The Basilical Chapel

The next phase of the chapel exhibits the skills of highly qualified craftsmen. The isolated piers, the archway, the spandrels that separate the nave from the aisles, and the east wall above the apse, are all constructed of a finely worked ashlar masonry. This has been dressed with chisels of about 3.5-4 cm wide with 10-12 teeth, in blocks which are typically about 30-40 cm high, and the full width of the column (66 cm) by half its width. Crosses and other motifs carved into this stonework are considered to date to about the 6th century. The original parts of the outer walls are of hammer-dressed blocks in well-ordered courses; typically the stones are about 22 cm high. These well-ordered blocks are found in other parts of the monastery buildings, including the rebuilding of the original watchtower, the south range of buildings, the terrace revetment near the chapel, the lower part of the terrace wall, indicating a lower terrace in this period, and a fragment of wall on the northeast edge of the terrace which was probably once a part of the diaconicon, where the priest would prepare for Mass. All of this work is not neccessarily all of one phase, but probably shows construction over the Byzantine period.


The fine carved cross in this block is characteristic of the 6th century. Note the surface of the stone which has been "dressed" by a chisel with "teeth" in it.

Phase Five: The Mediaeval Monastery

The greater part of the medieval construction on the site seems to be due to earthquake damage, and if the hypothesis that the clerestory of the nave of the church was made in its present form between the dates that bracket the paintings, then this would date the earthquake in the 12th century. Earthquake damage certainly seems to be indicated in a number of major cracks in the walls, and the actual collapse and subsequent rapid reconstruction of the walls. All of this masonry is of a similar nature, comprising undressed rubble and re-used blocks, and also including wood, indicative not of professional masons but of amateurs trying to rapidly shore up the remaining buildings. Apart from the clerestory and the pieces of masonry already suggested as being repair following an earthquake, other walls of the same nature include the rooms constructed over the aisles of the church, and the rooms below the present terrace. 

A 12th century date for the reconstruction works very well with the known seismic history of greater Syria. Major transverse faults may be found all along the region, while a major north-south fault on the same alignment is visible in the valley. During the 12th century a series of major earthquakes passed down the fault system from north to south. The Aleppo earthquake of 1138 is known as one of the most destructive earthquakes in recorded history. The Hama earthquake of 1157 is particularly well known in Middle Eastern history because it practically annihilated the Munqidh family of Shayzar. It is also recorded as being the first earthquake in which wood was incorporated into rebuilding. Each of these shocks caused widespread damage across the region, and could have caused the damage at Deir Mar Musa. The closest epicentre (which does not necessarily make it the most likely culprit) is an earthquake of 1170, while the Baalbek earthquake of 1202 was only 6 years before the completion of the wall-paintings in 1208. It is rather salutary to consider that the famous mural paintings of Deir Mar Musa al-Habashi were  created because of an earthquake that is known to have killed tens of thousands of people.

To the upper right of this image can be seen the repairs after the earthquake, with rubble masonry and wood typical of this sort of repair. The last phase of frescoes would have been over these repairs.

Building also appears to have been undertaken on the remains of the larger of the first two towers in about this period. This masonry comprises blocks which are well-dressed with a hammer and pecked, in well-lain courses of about 28-30 cm height. Small narrow windows all have a little detail of an arch cut into the top stone, and there is a small but effective box machicolation, situated directly over the door on the ground floor, already postulated as being medieval in its present form (see above). The vaulting in the ground floor of this structure would probably also be of this period. It seems probable that after the initial reconstruction following the earthquake, professional masons with experience of military architecture were employed to develop this defensive structure. The mediaeval modifications to the Bab al-Sharqi and Bab Touma in Damascus have similar stonework, windows, and box machicolations, the latter being of a suitably larger size. Both of these gates are particularly apposite comparisons as they also have foundations of large Roman blocks. 

This is a "box machicolation" a defensive structure made to allow defenders to drop things on people without attackers seeing them, it is positioned right over the door of this building, two stories below. The 15th century expansions put this feature inside the building.

This narrow window is typical of defensive architecture of the 13th-14th centuries.

Phases Six & Seven: Fifteenth century and later

In the late 15th century it is known that the monastery was producing a large number of manuscripts. Two inscriptions claim to have constructed a “fortress” on the site, one dated 1467/8 and located in the courtyard, the second over the present main entrance dated to 1497/8. There are indeed at least two further phases recognizable in the architecture at Deir Mar Musa which may fit this data. The final phase visible in the floor-plan is an extension that abuts the 15th century extension, which presently contains the lavatories, and presumably had this function when it was constructed.  Further inscriptions attest to intermittent activity until the abandonment of the monastery in the early 19th century.



Robert Mason, The Monastery of St. Moses the Abyssinian (Deir Mar Musa al-Habashi), Syria, Antiquity Vol 83 Issue 319 March 2009

Roman watch-towers

Y. Hirschfeld, The Judean Desert Monasteries in the Byzantine Period (Yale U. Press, 1992).


NAVIGATION (links will become hot as they are published)