The structure of the urban fabric of Aleppo is profoundly stratified and the relation of the city with history is an intimate one. It is not simply the presence of historic buildings and archaeological finds that makes this relation clear: the urban structure itself conserves marked traces of its past, which are legible through a structural reading of the building fabric.
This 'horizontal' reading is achieved by deconstructing the urban fabric in order to reconstruct its forms, trace its geometric laws and the ideas corresponding to each phase of its construction, and to rediscover the elements of the duality, or polarity, between the permanence of its signs and the variation of its meanings, that has shaped, physically and intellectually, the "urban-scape". From such a reading emerges that the form of the urban fabric of Aleppo is derived from a process, the phases of which, in pre-Islamic times, were determined by the land conformation of the environmental organism in which it is situated.
The first real human intervention in Aleppo was in the Hellenistic period, when the city was re-founded with the name of Beroea.
Fig. 1 : Aleppo: The first Roman plan secundum naturam. The Bab Qinnasrin area
Three different planning phases date to the Roman period, which were realised with different forms and orientations. The first stage coincides with the planning phase of the urban territory of Aleppo "secundum coelum". In this phase the urban and territorial structures merge. The urban-scape was articulated in an isotropic manner, beginning with two clear signs in both the urban and the agricultural fabric, the cardus and the decumanus. A reading of the structure of the urban fabric and territory of Aleppo shows the presence of a homogeneous and isotropic organization, based on a 710x710 metre module, which follows a north-south direction. The starting point for laying out this centuriation is the intersection between the Hellenistic via recta, the main decumanus, and the route along the eastern boundary of the first Roman block next to the Great Mosque, the main cardus. Measuring the urban fabric of the walled city we note that the two blocks immediately to the east of the Great Mosque have an anomalous dimension with respect to the blocks planned in the Hellenistic period. Their width is 71 metres, a measure which corresponds to two acta. The same rhythm may be read in the distance between many routes and in the orthogonal alignments of the urban fabric in a north-south direction. These alignments are widespread throughout the walled Mamluk city, especially in the fabric to the east of the citadel. The form of this first Roman plan represents a kind of 'squaring' of the city and territory of Aleppo, a structural grid more than an actual design.
The actual form of Aleppo was made by two further plans "secundum naturam" that followed this centuriation "secundum coelum". To the south of the Great Mosque, starting from one of the routes of the Hellenistic city, the direction of the urban fabric changes suddenly. The axis which, starting from this route, leads to Bab Qinnasrin, rotates considerably with respect to the north-south direction. Using the grid "secundum coelum", we can identify a territorial system based on a 710x710 metre module, rotated by 18° to the west with respect to the north-south axis. Since the Romans did not use degrees in their computations, the main axis of this centuriation "secundum naturam" can be identified with the hypotenuse of a right-angle triangle with a ratio of 1:3 (whose catheti correspond to 1 and 3 modules of the planning grid "secundum coelum"), starting from the intersection between the cardus and decumanus of the earlier planning phase. The dimension of the actus coincides with the rhythm of the urban fabric planned in this phase. The cardus in this organisation coincides with the Bab al-Nasr route and with the matrix of the settlement in the neighbourhood extra moenia to the north of the city, and is at a distance of two acta from the Bab Qinnasrin route, the gateway to Chalcis. The decumanus in this system coincides, outside the walls, with a ford, a route that starts from Bab Antakia, crosses the river, links up with the main route to Antioch, and then crosses the empty space immediately to the south of the citadel. An orthogonal of the decumanus coincides with the axis of the entrance to the citadel.
This planning marks the first major hiatus in the urban growth of Aleppo, since it is not continuous with the existing fabric, but has rotated it. The layout of the city in this phase, therefore, derives from that of the Syrian territory and from the direction of the territorial routes along the axis of the Syrian fault-line. Traces of this planning phase can be read near the Quweiq river and to the north of the city.
Fig. 2 : Aleppo: The second Roman plan secundum naturam. The Bab Qinnasrin area
In the intra moenia fabric of the city along the axis that leads to Bab Qinnasrin, we can still read the structure of the original aggregation. This axis was originally 25 Roman feet wide, and along it we can find traces of the substratum type of domus houses (17.7x35.5 metres), which are iso-orientated in an east-west direction, and set along this matrix route. Some of the planned building routes and connecting routes laid out in this phase can still be read in the neighbourhood structure. Some of these routes later became cul de sac.
A further Roman plan "secundum naturam" was carried out in order to adapt the urban and agrarian fabric of Aleppo to the course of the Quweiq river, that is, to a natural element of the site. This planning phase seems to be more widespread than the earlier one throughout the valley and urban fabric.
Starting from the network "secundum coelum", we can identify the main axis of this territorial system (of 710x710 metres), which is rotated by circa 10° to the west in respect of the north-south axis, with the hypotenuse of a triangle with a 1:6 ratio, starting from the intersection between the cardus and decumanus of the plan "secundum coelum".
This further rotation of the urban fabric is not as immediately evident as the one described above, since it is easily confused with the spontaneous fabric. It is, however, too widespread and extensive along the boundary walls of the Mamluk city to be casual, spontaneous or unplanned. The cardus in this system, probably a reverse axis in the urban fabric, is identifiable with an axis passing through Bab Antakia. Near this axis are archaeological remains dating to the Roman period, corresponding to the wall alignments that follow this organisation. The decumanus in this system might have been an axis passing through Bab Antakia.
This further organisation in the urban fabric of Aleppo, deriving from an agrarian plan which was almost immediately incorporated into the urban fabric, makes it easy to verify the actus as a unit of measurement.
In the area of Bab Qinnasrin we can read traces of this phase of the Roman organisation of Aleppo which makes a reading of its structure even more complex. Throughout the whole area within the aggregation, and even along a part of the Bab Qinnasrin axis, we can find traces of the iso-oriented domus lots of this planning phase, set in an east-west direction. On an architectonic scale, the structure of Bab Qinnasrin and of the khan next to it coincide with this organisation. The position of the plots within this area is not as rigid as that of the earlier phase, since this planning phase corresponds to the first 'restructuring' project carried out on the urban fabric of Aleppo.
The palimpsest of signs that makes up the urban fabric of Aleppo in pre-Islamic times is not an anomaly. Indeed, the superimposition of several centuriations in the same territory is a sequence typical of Roman territorial planning. In Aleppo, the superimposition of the Roman layouts determined a complex form for the urban fabric along the main axes of the road system within the walled city (Bab Antakia, Bab Qinnasrin, Bab al-Nasr), on which the Islamic city developed. These axes became linear nodes in Mamluk and Ottoman times, places epitomising the urban development and of specialisation and development of its urban form. These are the most interesting areas to analyse in order to reconstruct the process of formation of the Aleppo's urban fabric in time, and of the transformation from the pre-Islamic to the Islamic urban form.
Giulia Annalinda Neglia