The Mosque of the Three Doors, previously known as the Mosque of ibn Khayrun, was colloquially named after the three portals located along its famed west elevation. Its elaborate public entry is the oldest extant decoratively carved facade in the Islamic world, rendering the otherwise modest structure extremely significant to the modern study of North African architectural arts. The mosque was constructed during the ninth century CE (third century AH) under the Aghlabid dynasty ruling Ifriqiya, the coastal region comprising modern day Tunisia, western Libya, and eastern Algeria. The structure underwent a major renovation sponsored by the Hafsids during the fifteenth century CE (ninth century AH).

The Mosque of the Three Doors is located in the southeast of the Kairouan médina, approximately 400 meters south of the Great Mosque of Kairouan (836 CE / AH 221). Its western elevation opens onto a pedestrian street and hosts the mosque's arched entrance portals.

The mosque is almost rhomboid in plan, composed of four thick masonry walls enclosing a grid of vaulted bays. Unlike almost all North African mosques, the Mosque of the Three Doors is fully roofed and does not include a courtyard, likely due to its unusually compact footprint. The western street-front wall is 12 meters long, while the eastern qibla wall is 10 meters long. The mosque is 11 meters deep from east to west. The longitudinal axis of the structure is rotated 92 degrees clockwise from the north-south meridian to accommodate the orientation of the qibla wall.

A minaret is located at the northwest corner of the structure, projecting 1.5 meters from the face of the northern wall and rising 13 meters high. Added to the mosque in 1440 CE / AH 843, the minaret is similar in scale and ornamentation to other Hafsid minarets that were constructed throughout Ifriqiya. The minaret is roughly square in plan, measuring between 3.5 and 4 meters wide north-to-south and 3.75 meters deep east-to-west. A narrow stairway winds within the interior of the minaret to a small enclosed chamber located 8 meters above the ground, featuring screened openings framed by lobed arches. Decorative panels of green and white faience tiles in geometric patterns suggest a cornice and pilasters framing the twinned arches on the west elevation of the minaret. Such faience tiles are typical of Andalusian decoration, a vestige of the widespread artistic exchange between Spain and Ifriqiya during the fifteenth century. The minaret staircase opens onto a spacious balcony located 11 meters above the ground. The stairway is enclosed at the balcony level, its small square structure capped by a pyramidal tile roof and metal finial. The balcony is edged by 0.5-meter-tall stone merlons with pyramidal profiles, a form typical of Northern African or Andalusian battlements.

The three arched portals along the west elevation serve as the only entrances to the mosque's interior as it lacks a private imam's entry, typically located at one end of the qibla wall in North African mosques. The western elevation is symmetrically arranged, with the exception of the added minaret at its north end. A 3.25-meter-wide central arch is flanked by 2.5-meter-wide side arches. Each arched portal allows direct entry into the prayer hall.

The interior of the mosque continues the tripartite organization of the west elevation, as the prayer hall is divided by columns into three aisles, each three bays deep. Each bay is roofed by a corbelled stone dome reaching a maximum interior height of 4.5 meters. The columns from which the domes rise are each 2.5 meters tall. Each bay measures approximately 2.5 meters square, with a slight deflection to accommodate the skew of the column grid in plan. The central bay of the prayer hall is edged by a slim partition along its west side, preventing a direct view of the qibla niche from the central entry and the street.

Narrow niches are inset into the north, east, and south walls between the columns that support the perimeter domes. The niche at the southwest corner of the mosque has been partitioned off as a small storage space, while the northwest corner is occupied by the ground level entrance to the minaret's enclosed stair. The qibla niche is located in the center of the east wall, between two small ornamental columns. The opening into the niche is 1.25 meters wide, while the niche itself is circular in plan with a 1.5 meter diameter. The niche projects 1.25 meters into the 1.5-meter-thick east wall.

The mosque is a stone masonry structure laid in a coursed ashlar pattern. With the exception of limited colored tilework on the minaret and within the qibla niche, the entire structure is constructed of a soft white stone that is local to the area and easily carved. The use of this material enabled the ornamentation for which the mosque became renowned: the frieze and cornice above the three gates.

Within each of the three blind arches on the west street-front is a rectangular doorway bordered by a flat stone enframement. The lobed arches rest on repurposed antique stone columns and capitals dating from pre-Islamic Kairouan. Above the arches, the wall features intricate decorative carving of the same soft white stone used in the masonry structure of the building. A pattern of small lobed leaves and vine tendrils fills the space between the tops of the arches and the first band of Kufic inscription that forms the base of the 2-meter-tall frieze. The frieze is composed of four major bands of carving, each 0.5 meters tall; two rows of inscriptions are located below a central row of geometric and vegetal patterns, which is topped by a third row of inscriptions. The inscriptions reveal details about the construction and dedication of the mosque, attributing its erection and original name to Mohammed II ibn Khayrun (reg. 863-875 CE/AH 250-261). A portion of the inscription was added in 1440 to credit the construction of the minaret and general renovation of the structure to the Hafsid ruler Uthman bin Muhammad al-Mansur (reg. 1435-1488 CE/AH 839-893). Above the frieze, a 0.5 meter-tall row of carved dentils supports a simple 0.25-meter-tall cornice that projects 0.5 meters from the face of the wall.

Today the mosque remains open as a place of worship. Though tourists are restricted from viewing its interior, they may still visit to enjoy the structure's most significant architectural feature, its ornate public facade. Though the soft stone carvings have suffered some erosion during the centuries since its construction, subsequent restorations and attention to the structure's preservation in the modern era have allowed the carvings to remain in excellent condition. The Mosque was designated an UNECSO World Heritage Centre in 1988, along with the entirety of the Médina of Kairouan.

Sources:

Bosworth, Clifford Edmund. The New Islamic Dynasties. New York: Columbia University Press, 1996. 31-32, 45-47.

Ettinghausen, Richard, Oleg Grabar, and Sheila Blair. The Art and Architecture of Islam: 650–1250. New York: Penguin Books, 1987. 101.

Maison tunisienne de l'edition. Mosques de Tunisie. Tunis: Maison tunisienne de l'edition, 1973. 120-121.

Michell, George. The Architecture of the Islamic World. London: Thames & Hudson, 1978. 70, 220.

Museum With No Frontiers. Ifriqiya: thirteen centuries of art and architecture in Tunisia. Vienna, Museum With No Frontiers, 2002. 152-155, 158-159.

"Kairouan" The Grove Encyclopedia of Islamic Art and Architecture. Ed. Jonathan M. Bloom and Sheila S. Blair. © Oxford University Press 2009. The Grove Encyclopedia of Islamic Art and Architecture: (e-reference edition). Oxford University Press. Massachusetts Institute of Technology (MIT). http://www.oxford-islamicart.com/entry?entry=t276.e459. [Accessed 18 March 2011]

Saloua Zangar. "Mosque of the Three Doors" in Discover Islamic Art. Place: Museum With No Frontiers. 2010. http://www.discoverislamicart.org/database_item.php?id=monument;ISL;tn;Mon01;26;en. [Accessed 18 March 2011]

United Nations Education, Scientific and Cultural Organization. 2011. Kairouan. World Heritage List. http://whc.unesco.org/en/list/499. [Accessed 18 March 2011]