This text was written in collaboration with Antonio Almagro, Profesor de Investigación ad Honorem (Escuela de Estudios Árabes, CSIC) and member of Real Academia de Bellas Artes de San Fernando.
In the western Islamic tradition, timber structures were used to cover the most important spaces in certain buildings, such as the naves of mosques or the halls of palaces. These structures played a major role in the decorative programme of these spaces. Three structural systems were most frequently used: these were alfarjes (horizontal panelled ceilings with beams); armaduras de par y nudillo (rafter and collar truss ceilings); and taujeles (flat wooden boards decorated with geometric motifs and nailed to a structural frame). This blog will focus on the second of these systems, armaduras de par y nudillo, and in particular in the architectural context of present-day Morocco, where this type of ceiling is known as barjla.
The wooden ceilings preserved in religious buildings – mosques, madrasas (religious schools) and zawiyas (shrines of saints) – in the Maghrib (western North Africa) constitute a legacy of great value, as some may be as old as the 12th century, a period from which it is very uncommon to have examples preserved in the Iberian Peninsula. However, there has been no focused study of ceilings in present-day Morocco – they have been referred to in architectural studies, but research on these ceilings has been hampered by the difficulties of public access to religious buildings. Permits to enter must be obtained from the Moroccan Ministry of Awqāf and Religious Affairs, but even then researchers can only spend a limited amount of time inside the building, which may also be intermittent due to prayer times, so that conducting fieldwork can be slow. Our own research has been possible thanks to several research projects aimed at documenting architecture from the Almohad, Marinid and Saadian periods, that is from the mid-12th to the mid-17th centuries. While we have not yet undertaken specific research on wooden ceilings, we have been able to document significant in-situ examples.
However, firstly, it is important to note that, at some point in the 12th century, a series of technical innovations were introduced in the way these timber structures were built and decorated. The exact sequence of these innovations is unknown, but they can be characterised by four substantial changes that led to the prevalence of one system (that of par y nudillo) over the others.
The first of these changes was that the technique of placing each rafter with its corresponding tie-beam directly upon a wall was replaced by first laying two longitudinal timber sections or brackets (estribos) upon which the rafters were set. This allowed the tie-beams to be spaced further apart and independently from the rafter sequence, therefore making the pitched structure more visible while also reducing the amount of timber needed for these structures.
The second innovation was that a new system was adopted. It was based on the use of rafters and collar trusses, but now cuts were made in them (known as gargantas and cornezuelos) that allowed for their assembly, and making it easier to join together several pieces simultaneously. This, along with the layout of double hips (limas moamares), allowed entire parts of the structure – both the flat horizontal part (almizate) and the slopes (faldones) of the ceiling – to be prefabricated in a workshop, making it easier to mount everything on site.
The third change was the introduction of geometric decorative motifs made with interlacing peinazos (strips of wood that bridge other pieces) and decorated strips of wood. These patterns were initially simple eight-pointed stars, and evolved over time into more complex forms. These geometric interlacing techniques were drawn from craft practices across different media in the Islamic world. Their integration with northern European carpentry techniques is what makes the roofing practices of al-Andalus and the Maghrib so distinctive.
Finally, although it is difficult to verify today, it is also possible that the carpenters could have used cartabones (triangular rulers). These tools allowed the outlining of the cutting lines of structural pieces and geometric interlacing, and facilitated the carpenter’s work by ensuring precision when tracing a complex design.
The oldest known examples of this building system can be dated to the 12th century and most of them are located in the Maghrib, as we will discuss below. However, it is intriguing that similar structures, albeit more primitive in design, appear to have been built at more or less the same time in Toledo, on the Iberian Peninsula. This may indicate the simultaneous development of the technique across Iberia and the Maghrib in the early medieval period.
The 12th century – when the main technical and decorative traits of par y nudillo roof frames appear – was a period of great architectural splendour in the Western Islamic world, for two reasons. First, Ibn Mardanīsh (r.1147-72) proclaimed himself the independent ruler of Sharq al-Andalus, the eastern region of Islamic-ruled Iberia. His capital was at Murcia, and he was a prolific builder of fortresses, palaces and estates. At the same time as Ibn Mardanīsh emerged, a new dynasty, the Almohads, were consolidating their rule in Marrakesh and extending their domains over western North Africa and Islamic Iberia – they later annexed Ibn Mardanīsh’s territories. The Almohads erected numerous religious, civic and defensive buildings, to such an extent that this period has left a significant built legacy in the medieval Islamic west. Among all this intensive building activity, only four examples of 12fth-century par y nudillo roof frames have survived to our day.
One of them – which might be the oldest – is the wooden ceiling from the palace of Pinohermoso in Xàtiva, near Valencia, which is now installed in the Museo de Bellas Artes in Xàtiva. This structure originally covered the hall of a private residence and was accompanied by a double-arched opening leading into the space, creating an ornate ensemble that has been attributed by several authors to the reign of Ibn Mardanīsh.
This frame lacks tie-beams, which could weaken its structure, although in this case it does not seem to have been a major disadvantage, since the span of the room is relatively small (around 3 m), and its nudillo (collar) and estribo (bracket) are well embedded within thick walls, ensuring sufficient rigidity. The ceiling was set upon a simple arrocabe (frieze) made with a single alicer (panel covering the wall at the level of the tie-beams and corbels). The almizate (horizontal central part of the ceiling) differs greatly from the faldones (slopes): while the former is composed entirely of interlacing peinazos, the latter are covered with alfardones (hexagonal panels).
The ornamentation is concentrated in the modules of the almizate, whose composition follows a staggered pattern of crosses set at a 45º angle and eight-pointed stars in the middle, with small concave domes. Its most significant characteristic is the polychrome work, with different vegetal motifs painted on the alfardones, small arches and palms on the tabicas (small boards arranged vertically above the arrocabe to close the remaining gaps between the rafters), and pearled outlines on the different geometric shapes.
The second example of par y nudillo ceilings we want to discuss can be found in the Kutubiyya mosque in Marrakesh.
The construction of this building began in 1158 under the reign of ʿAbd al-Muʾmin (r.1130-1163), however, sometime before 1163 this same sovereign undertook its extension towards the south, doubling the size of the original building.
The works were concluded by his successors Abū Yaʿqūb Yūsuf (r. 1163-1184) and Abū Yūsuf Yaʿqūb al-Manṣūr (r.1184-1199).
One reason for the building’s significance is the ensemble of ceilings that cover the nave along the qibla wall (the wall of the mosque that indicates the direction of prayer). Here we can observe a sequence that alternates five plaster domes decorated with muqarnas, and four timber roof frames.
Ever since the first studies of the building began in the 20th century, there has been speculation about the possible Almohad date of these wooden ceilings, in accordance with the dating of the building. The walls upon which these structures sit have plaster friezes with geometric patterns based on eight-pointed stars.
The wooden ceilings were assembled with tie-beams placed on corbels, the distance between which changes in the two central structures.
The aliceres placed at the level of the corbels are decorated with horseshoe and multifoliated arch motifs, as well as bosses, outlined with vegetal forms.
The faldones (slopes) are executed mostly with simple boarding, using interlaced strapwork only in their almizates (the flat central section). However, there are differences between the pair of ceilings closest to the mihrab, and those on the east and west sides. The two central roof frames present designs of eight-pointed stars, alfardones (hexagonal panels) and almendrillas (diamond shaped geometric forms), while the two lateral ceilings have a design of octagons where the rafters and peinazos cross.
The decorative layout of the interlaced strapwork in the central pair of ceilings is common in other ceilings from both the medieval and early modern periods, which has led to speculation that they might date from a later period. However, the design of the two lateral ceilings is highly unusual, and has led to more questions being raised about their date, and where they could be placed on the timeline of the evolution of timber roof frames.
In fact, these designs do resemble other Almohad ceilings, such as the third example of par y nudillo roof frame we would like to briefly mention.
This is a structure found in the Great Mosque of Tlemcen (Algeria), documented in 1979 by Lucien Golvin (1908-2002), a French art historian and specialist in the Islamic architecture of North Africa. The mosque was founded at the end of the 11th century, under the Almoravid regime which preceded that of the Almohads. However, the mosque underwent interventions during the Almohad period. One such intervention could be this wooden ceiling, which has the same octagonal-patterned strapwork as that seen in the Kutubiyya. A fuller study of this mosque and the ceiling documented by Golvin is eagerly awaited!
The fourth and last example of par y nudillo roof frames from the 12th century can be found in Fez, Morocco. The city possesses medieval architectural heritage of great value, which remains unexplored to a large extent. Just recently we have learned of the existence of an Almohad ablutions hall forgotten by the academic world. The space in question was erected opposite the northern gate of the al-Qarawiyyīn Mosque, one of the most important congregational mosques in North Africa. Founded in the 9th century, significant extensions were added during the 10th century and early 12th century, under the Almoravids. Written sources also indicate that works were undertaken on the mosque during the Almohad period, for example domes in front of the doors and a monumental fountain in the court. Potentially, some of the ceilings in the prayer hall could also have been renovated at this period.
The construction of the ablutions hall seems to have occurred during the reign of the Almohad caliph al-Nāṣir (r. 1199-1213). It is organised around a central atrium where the fountain for ritual ablutions before prayer is located. Being the most noble part of the building, it is covered by an impressive timber roof frame. This ceiling shares notable similarities with the roof frames of the Kutubiyya Mosque. At a structural level, its design consists of a rafter and collar truss with double hip rafters, two pairs of tie-beams, corbels and double angle ties at the corners (cuadrales). As for its decoration, the arrocabe is composed of a single alicer adorned with a series of small simple, double and mixed arches, outlined with intertwining vegetal motifs.
The boarding in the space between the rafters is decorated with elongated alfardones (hexagonal panels), while the almizate is bridged in all directions using interlaced strapwork based on an octagonal pattern where the rafters and peinazos cross.
These structural and decorative details point to significant similarities between the execution of this ceiling, the two lateral ceilings in the Kutubiyya Mosque, and the ceiling in Tlemcen documented by Golvin. At a technical level, they share a solution that is common in countless ceilings built in Iberia and the western Maghrib over the course of many centuries. However, two decorative features could narrow down the timeframe of their execution, making their Almohad dating quite possible. First, the type of interlaced strapwork is the same across the three Almohad buildings presented here. Second, the small arches decorating the aliceres are very similar to those from the former Almohad Mosque of Seville (now the cathedral), which was constructed in the 1170s, just slightly later than the Kutubiyya Mosque. Two aliceres have been excavated in the patio of the former mosque, which also preserve a design of small polylobed arches. We know from medieval texts and documents that the Almohad mosque of Seville was roofed throughout with timber roofing frames, which seem to have been of the rafter and collar truss technique. This is also confirmed by the archaeological traces of paired tie-beams and arrocabes left on the walls.
This small set of significant examples offers the chance to characterise the emergence of a particular type of roof frame in the 12th century, on the Iberian Peninsula and in North Africa. The ceilings closest to the qibla at the Kutubiyya mosque (see image above) – whose date has been disputed by many – are therefore likely to belong to the Almohad period. This hypothesis is reinforced by the existence of contemporary parallels, including the identical roof frames in Tlemcen and the ablutions hall in Fez.
The role that the Almohad period played in the development of carpentry in the Islamic west is obviously significant, because no earlier examples of par y nudillo ceilings are known to us. Before this date, it seems that alfarjes or ceilings formed from simple trusses (made with two rafters and one tie-beam) were the commonplace. These are found, for example, in the ceilings of the Umayyad Mosque of Córdoba (8th to 10th centuries), or the Almoravid period ceilings of the Tlemcen mosque (late 11th/early 12th century). In therefore seems to be precisely in the Almohad mosques of the later 12th century where the par y nudillo roof frames with double tie-beams begin to appear.
Identifying the origin of 12th-century wooden ceilings also allows us to understand their subsequent development in Iberia and North Africa, during the rule of later dynasties such as the Nasrids in Granada (13th to 15th centuries), or their contemporaries the Marinids in present-day Morocco, or the Saadians in the western Maghrib (16th to 17th centuries).
Nevertheless, the carpentry tradition was also significant in northern Europe, an aspect that makes us wonder whether the technical details for making par y nudillo ceilings with tie-beams do not have their origin in the Andalusi-Maghribi context, but might have originated further north and been transmitted through the Iberian kingdoms. They were eventually integrated by the Almohad workshops – whether first on the Iberian Peninsula or in North Africa is not possible to tell. Here they were combined with the pre-existing tradition of geometric interlacing, to give rise to a new ceiling model that would enjoy great success in the Islamic West over the coming centuries. In this regard, the ceiling from Pinohermoso with which we started might represent a moment of convergence of artisanal traditions, as its likely patron, Ibn Mardanīsh, maintained good relations with the Christian kingdoms. Was this the moment at which the transfer of skills into Islamic architecture took place?
