Discover Iran: Kharraqan Twin Towers in Qazvin and the brilliance of Iranian brick architecture

By Ivan Kesic

• The Kharraqan Towers are considered the earliest examples of double-shell domes in Iran, with the two-shell system separating the structural and external architectural functions of the dome.
• The external decoration of the twin towers features more than sixty types of brickwork, making them effectively a "museum of Iranian brickwork" with intricate geometric patterns, pointed arches, and Kufic inscriptions.
• Inside the eastern tower, some of the most well-preserved examples of early Seljuk mural painting survive, including depictions of a mosque lamp, peacocks, the tree of life, and six- and eight-pointed stars in blue, black, and brown colors.

Standing on the open plains of Qazvin Province, the twin Kharraqan Towers represent one of the most extraordinary achievements of Seljuk architecture, a masterful synthesis of geometry, brickwork, and structural innovation that continues to captivate scholars and visitors nearly a thousand years after their construction.

Located approximately one kilometre from the village of Hesar-e Vali Asr in Avaj County and about thirty-two kilometres from the Qazvin-Hamadan road, the towers rise from an otherwise barren landscape, silent witnesses to the architectural brilliance of eleventh-century Iran.

These twin funerary monuments, standing just twenty-nine metres apart, form an unusually coherent architectural ensemble, one that has been aptly described as a “museum of Iranian brickwork.”

The eastern tower, the older of the two, dates to 460 AH (1068 AD), while the western tower was completed twenty-five years later, in 486 AH (1093 AD). Their close proximity and remarkable visual harmony, combined with subtle differences that reveal an evolution in architectural thinking, make them one of the most significant surviving ensembles of Seljuk architecture.

Despite the loss of their original exterior domes, the devastating effects of earthquakes, and the passage of nearly a millennium, the Kharraqan Towers retain their remarkable grandeur. Their intricate brickwork and innovative construction continue to offer invaluable insights into the technical sophistication, geometric mastery, and artistic sensibility of their builders.

Architects and their patrons

The Kharraqan Towers are exceptionally valuable to the study of Iranian architectural history because their inscriptions preserve the names of both their builders and patrons, providing an unusually firm chronological and biographical framework.

The eastern tower bears a two-line inscription dated 460 AH (1068 AD) and naming Mohammad ibn Makki al-Zanjani as its builder. The western tower carries an inscription dated 486 AH (1093 AD), identifying Abol-Ma'ali ibn Makki al-Zanjani as its architect.

The striking similarity between the two names suggests that the architects were probably related, possibly father and son or brothers, which may help explain the remarkable architectural continuity between the two monuments. Their shared name also offers a rare glimpse into the transmission of architectural knowledge and craftsmanship within medieval Iran.

The later identification of the towers with two Seljuk amirs -- Abu Sa'id Bijar ibn Sa'd in the eastern tower and Abu Mansur Iltayti ibn Tekin in the western tower -- further indicates their association with the military elite of the Seljuk period.

The survival of the builders’ names is particularly significant. The identities of medieval Iranian architects and craftsmen are often absent from the monuments they created, making the Kharraqan inscriptions unusually important historical evidence.

Together, these inscriptions connect the towers to identifiable individuals and provide a rare foundation for tracing the development of Seljuk architectural practice, craftsmanship, and design across the late eleventh century.

Octagonal plan and double-shell domes

The most important architectural innovation of the Kharraqan Towers lies in their use of double-shell domes, which the study identifies as the earliest examples of this construction technique in Iran.

The two-shell system separates the structural and external architectural functions of the dome, allowing the builders to create a substantial outer profile while maintaining an efficient inner enclosure.

The eastern tower has two stairways, while the western tower has a single staircase, representing one of the clearest structural differences between the two monuments.

The staircases themselves are evidence of the towers' complex internal organization, with the eastern tower containing two spiral staircases within its buttresses and the western tower containing only one.

In the eastern tower, the stairs are built in a clockwise spiral with 21 to 22 steps, each about 30 centimetres high and 52 centimetres wide, leading to a narrow corridor located in the space between the inner and outer domes.

The western tower's staircase has 24 steps, and its single stairway appears to have given the later building a structural advantage that contributed to its better state of preservation.

The exterior domes of both towers have collapsed, but the inner domes remain, preserving the curvature that begins at the upper end of the octagon and reaches a height of more than 3 metres.

Both towers employ an octagonal plan, with the external octagon transforming into an approximately circular interior and ultimately into the domed upper structure.

Each tower has one principal axis of symmetry and a single entrance: the eastern tower's entrance faces northeast, while the western tower's entrance faces north.

The octagonal geometry is especially important in the development of Iranian funerary architecture because it provides a compromise between the structural advantages of a polygon and the visual continuity of a circular dome.

The use of pilasters, or attached semicircular columns, at the external corners strengthens the perception of the tower's upward movement while also breaking the otherwise flat surfaces of the octagon into distinct architectural faces.

Art historians regard this transition from circular to polygonal planning as a significant architectural development, as many funerary towers in northern Iran during the fourth and fifth centuries AH (10th and 11th centuries AD) employed circular plans.

The Kharraqan Towers instead use an octagonal form, while retaining the circular logic necessary for the dome, producing eight relatively flat exterior surfaces that can be treated as individual decorative fields.

The result is particularly important for brick decoration because a flat octagonal wall offers considerably more manageable surfaces for geometric patterns than a continuously curved cylindrical wall.

Geometry of harmony

The proportional relationships of the Kharraqan Towers reveal a sophisticated understanding of numerical harmony embedded within Iranian building traditions.

According to the professional measurements and analysis, the eastern tower was originally approximately 18 metres high, with an external octagonal side measuring about 6 metres and an internal dimension of roughly 4 metres.

The western tower was originally nearly nineteen and a half metres high, while its external octagonal sides are likewise about 6 metres and its internal dimension about 4 metres.

The later western tower is approximately one and a half metres taller while maintaining essentially the same basic horizontal dimensions, evidence of a common architectural conception.

The ratio of dome height to body height is 1:2, while the ratio of body height to total height is 2:3, and the researchers further identify a 1:2:3 proportional relationship within the design system.

These ratios suggest a sophisticated approach to numerical harmony, although whether they were consciously calculated as a formal proportional system or emerged through traditional architectural modules and empirical practice remains uncertain.

The proportional relationships, particularly the 1:2 and 2:3 relationships, give the towers an overall harmony that links their individual components into a coherent whole.

Whether these were consciously calculated according to a formal numerical system or emerged from traditional architectural modules and empirical design remains a more complicated historical question, but the effect is unmistakable: the Kharraqan Towers embody a remarkable sense of balance and proportion.

Museum of Iranian brickwork

The external decoration of the Kharraqan Towers is perhaps their most celebrated feature, with more than sixty types of brick decoration identified across the two monuments.

The walls of both towers are approximately 60 centimetres thick, with the decorative brick covering an additional 21 centimetres. The bricks themselves are about 19 to 20 centimetres in size, with a thickness of about 5 centimetres, and the mortar width usually varies between 1 and 2 centimetres.

These relatively standardized units allowed the builders to create complex patterns while maintaining the structural continuity of the masonry. The external surfaces are divided into framed panels, arches, and geometric fields, creating a remarkable visual rhythm across the eight sides of each tower.

Among the identified motifs are herringbone or woven patterns, pointed-arch patterns, square knots, and numerous other geometric configurations.

The later western tower also employs framed pointed-arch motifs and three-lobed triple patterns, demonstrating the evolution of the decorative vocabulary between the two buildings.

The circular columns also have decorative brickwork, and the dome stem is made up of two parts which contain brickwork geometric designs and an inscription in Kufic script.

Each of the eight facades of the two towers is adorned with a decorative panel, and all panels are distinguished by a different decorative pattern but unified in their use of brick as the primary constructive element.

The brickwork recalls the earlier Mausoleum of Ismail the Samanid in Bukhara, but at Kharraqan the repertoire is considerably more elaborate, with deeply recessed mortar joints and a wide variety of star-shaped, polygonal, interlaced, and other geometric patterns.

This decoration was not simply applied to an otherwise complete building; the brickwork and the geometry of the building were deeply interconnected.

Because the towers were octagonal, each face became an independent field that could accommodate a carefully composed pattern.

The corner pilasters created additional vertical divisions, while the recessed and projecting brick courses produced changing shadows as sunlight moved across the facade.

The facades are so extensively articulated through decorative brickwork that the towers rank among the most striking surviving monuments of Iran's early Seljuk architecture.

The common feature of the panels in both towers is a decorative niche flanked by a pair of slender columns.

In the western tower, the panel within the niche has been divided into two parts by three small, slightly protruding, arched niches, while in the eastern tower, built first, these panels have been left uninterrupted and only include one pattern per panel.

The extraordinary execution of the brickwork testifies to the technical skill of its makers and materializes the art of the fifth century AH (11th century AD), with a new method applied in brickwork that was then used in making buildings such as the Maragheh Red Dome.

Calligraphy and the divine word

Common to both towers is a line of Kufic inscriptions in Arabic that runs the entire perimeter of the buildings above the arches, interrupted only by the corner pilasters.

On the eastern tower, the writing has been identified as the last three verses of Surah 59 of the Holy Quran. The western tower is decorated with the same verses from Surah Hashr, written in Kufic script.

The entrance of the eastern tower features an inscription written in three lines in Kufic script, and above the entablature of the western tower, a part of verse 115 of Surah al-Mu'minun is written in Kufic script.

On the eastern tower, in front of the entrance, the word Allah appears nine times to decorate the main doorway, and in the corners of the arch are two medallions with different brickwork.

The Kufic inscriptions provide a powerful visual and spiritual dimension to the monuments, integrating the divine word into the architectural fabric.

The combination of geometric brick patterns and calligraphic inscriptions demonstrates the integration of architecture and sacred text characteristic of Islamic art in Iran.

Interior frescoes and symbolism

Inside the eastern tower, the interior walls preserve some of the most remarkable examples of early Seljuk mural painting, presenting a rich iconographic program that has survived despite the passage of nearly a millennium.

The interior of the building is covered with a white plaster coating on which colorful paintings are painted, with the plaster covering darker in some parts, including the lower parts of the building or in the part where the octagonal becomes hexagonal.

Each wall has a rectangular panel inside which there is a chevron arch that is divided into two parts; in the lower part, there is an image of a censer or the tree of life with four birds symmetrically, and in the upper part there are medallions with images of one or two peacocks, and six- and eight-pointed stars.

In the transitional part, small panels with a chevron design are seen that have an inscription in Kufic script. The paintings are mostly in blue, black, dark and light brown and show the picture of a mosque lamp, peacock, six-pointed stars, eight-pointed stars, pomegranate tree, and flowers and bushes.

The iconography of these paintings carries profound symbolic meaning. The depiction of a mosque lamp hanging with three chains, inscribed in Kufic with the words "Blessing to its owner," is considered by some scholars to be a symbol of God based on Surah An-Nur.

The tree of life motif, painted with fruits on its branches and birds in pairs facing each other, is another symbol of Paradise. The image of peacocks within the medallions on the walls inside the building has been interpreted as a symbol of fertility, spring, paradise, and even the sun.

The interior of the western tower, in contrast, lacks the elaborate plaster and painting of the eastern tower, with the same brick pattern used for decoration instead.

The only stucco decorations of the western tower are the use of continuous scroll designs in the form of a narrow rectangular string on each of the eight sides and on the lower part of the panel of the first side.

A painted altar on the fifth side is a rectangular panel with a high-quality brick archway inside, demonstrating that even in the more austere interior of the western tower, architectural decoration remained a priority.

The presence of these murals in the eastern tower is particularly significant, as they are among the most well-preserved examples of Seljuk painting in Iran and provide rare evidence of the decorative schemes that once adorned many Seljuk monuments.

Kharraqan Towers in the longer tradition

The Kharraqan Towers belong to the mature phase of an architectural tradition that had already emerged in Iran by the late tenth and early eleventh centuries, well before the Seljuks established their empire.

The earliest examples demonstrate that the idea of expressing a mausoleum through a prominent brick tower was already being explored under regional dynasties such as the Ziyarids, Bavandids, and Kakuyids.

The Gonbad-e Qabus, erected in 1006 by the Ziyarid ruler Qabus ibn Voshmgir, represents one of the earliest and most monumental surviving expressions of the form, with its tall decagonal exterior, cylindrical interior, and conical roof creating a radically different silhouette from the Kharraqan Towers, yet both share the fundamental concept of the vertically emphasized brick funerary monument.

The Bavandid towers of Resket, Radkan, and Lajim, constructed in 1016, 1020, and 1022 respectively, as well as the Ziyarid Pir-e Alamdar at Damghan, dated 1026, demonstrate that the tradition was not confined to a single dynasty or locality.

Their cylindrical bodies, domed or originally conical roofs, brick construction, ornamental surfaces, and inscriptions establish a regional vocabulary from which later Seljuk architects could draw.

Gonbad-e Ali at Abarkuh, dated 1056 and associated with the Kakuyids, is especially interesting because its predominantly stone construction shows that the funerary tower concept was more important than any single material; its octagonal exterior and domed composition provide a particularly useful comparison with the later Kharraqan form.

The Kharraqan Towers transform the octagonal funerary tower into an exceptionally elaborate exercise in geometric brick architecture. Their relationship to the earlier monuments is evident in their basic typology, but their decorative treatment is considerably more complex.

The comparison with contemporary or slightly later Seljuk towers reinforces this point. The Chehel Dokhtaran Tower at Damghan, dated 1054, retains the funerary-tower function but has a circular rather than octagonal body; the Mehmandust Tower of 1097 similarly uses a polygonal exterior—dodecagonal rather than octagonal—with a circular interior.

The towers at Golpayegan and Karat demonstrate that closely related geometric and brick-building techniques were not restricted to mausoleums, but could also be employed in towers interpreted as guide beacons and watchtowers.

The Shebeli Tower at Damavand illustrates how an earlier monument could acquire a Seljuk-period architectural skin.

The Samiran Twin Towers, also in Qazvin Province and from the 11th century, provide an especially important link to Kharraqan, with comparative research suggesting that the Kharraqan monuments inherited and developed the earlier Samiran towers' plans, forms, proportions and geometric principles.

In this sense, Kharraqan stands at an important intersection: it inherits the funerary tower tradition of pre-Seljuk Iran while pushing the decorative possibilities of Seljuk brick architecture toward a new level of complexity.

The towers should consequently be understood not as an isolated Seljuk invention but as one of the most accomplished products of a longer Iranian experiment in transforming brick, geometry, and writing into monumental architecture.

They are a testament to the continuity of architectural knowledge in Iran, where regional traditions, inherited techniques, and new political patronage combined to produce some of the most extraordinary buildings of the Islamic world.

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