Entering through immensely tall bronze doors, many inlaid with silver and gold, visitors passed into silent, imposing courtyards, then entered darkened sanctuaries lit by dozens of softly glowing glass lamps. Suspended from high ceilings on chains invisible in the darkness, the enameled and gilded lamps would have appeared to float in space, providing a soft, even light conducive to prayer, meditation and awe.

Whether luxurious or humble, all of Cairo’s medieval mosques served as places of meeting and of worship. But some did more. In the early Islamic city, a congregational mosque, or masjid jami‘, endowed by its founders and well-kept by a staff of sextons, was designed to accommodate all the local inhabitants for Friday prayers. Open to all, this large building also became the locus of public education, and here all the sciences of the day were taught. The congregational mosque also played an important social role, for it sheltered the homeless and served as a meeting place for the discussion of matters affecting the community.

In Egypt, the first congregational mosque was built about AD 641 by the conqueror ‘Amr ibn al-‘As in his new town of Fustat, now at the southern end of modern Cairo. The second is today the earliest mosque still standing; it was finished in 879 by Ahmad ibn Tulun for the palace-city of al-Qata’i‘.

Originally from the Central Asian caravan entrepôt of Bukhara, Ahmad ibn Tulun’s father rose in the service of the Abbasid caliphs of Baghdad. Ibn Tulun was educated in Tarsus, in Anatolia, and then appointed in 868 by the caliph to govern his Egyptian domains. Two years later this ambitious young man set himself up as an independent ruler intent on rivaling the regional power of his former Abbasid master.

In doing so, Ibn Tulun was the first ruler of the Islamic era to give Egypt a sense of its past importance. Just beyond the old capital of Fustat, al-Qata’i‘ became renowned as one of the wonders of the age. Set amid splendid gardens were palaces, barracks, a hospital, a huge maydan (public square)—where Ibn Tulun and his men played polo—and the mosque, of unprecedented proportions. To finance his grand project, it is said Ibn Tulun used wealth from a sudden discovery of treasure—probably a cache of Pharaonic gold.

Set on a rocky spur, the mosque was built of fired brick and modeled on the great mosques Ibn Tulun had known in the caliph’s palace-city of Samarra, now in Iraq. A person coming to pray across the rock-strewn desert from nearby Fustat entered through two enormous parallel outer walls. The space between them is called the ziada, and was designed to keep out the heat, dust and noise of the profane exterior world. Here the teaching of theology, medicine, astrology and grammar took place. This was also where ablutions were performed before entering into the mosque proper to pray. Set into the walls were 128 finely carved, stucco-grilled windows, which filtered the sunlight through delicate tracery.

Once inside, the visitor was shaded in long aisles formed by a forest of 220 gigantic brick piers topped by pointed, slightly horseshoe-shaped arches, all decorated in the style of Samarra. (Two hundred years hence, such arches would appear for the first time in Europe’s Gothic cathedrals and, later, in the Arab structures of Andalusia.)

Beyond the shaded arcades was a vast, silent, sunlit courtyard. In its center stood an elaborate fountain where visitors refreshed themselves and where, on hot summer days, they could partake of sweet lemon drinks. To ensure that plenty of fresh water was available for the mosque and all of al-Qata’i‘, Ibn Tulun built an aqueduct, also out of mud brick, stretching far across the desert to a spring at Basatin. The mosque was a haven for mind, body and spirit.

Beyond the courtyard, attached to the inner of the courtyard’s double walls, was a minaret with a spiral staircase on the outside—again in imitation of Samarra.

Over the centuries, additions and restorations by others bore witness to the importance of Ibn Tulun’s mosque. The Fatimids added a magnificent commemorative stele with boldly floral Kufic inscriptions. The Mamluks redecorated the interior of the mihrab, or prayer niche, and the mimbar (pulpit) they added is thought by many to be the most beautiful in the city. They reconstructed the minaret, and they rebuilt in stone the wooden central fountain that had been destroyed by fire at the end of Ibn Tulun’s rule.

Ibn Tulun’s dynasty collapsed in AD 886, and al-Qata’i‘ was razed. All that remained was the mosque. Over the next 1100 years, it withstood fire, flood and earthquake, and it is now surrounded by the city named by Ibn Tulun’s successors al-Qahira, “the vanquisher”—Cairo.

he first mosque built by the Fatimids in al-Qahira was al-Azhar, “the most resplendent” or “the most blooming,” founded in AD 972. It quickly took precedence over all other mosques, and for more than a thousand years, students have gathered around its columns seeking knowledge from famous scholars, making it one of the oldest universities in the world.

With their conquest of Egypt, the Fatimids also claimed the Islamic caliphate, and other large mosques were built: That of al-Hakim, outside the walls of al-Qahira, was nearly as large as Ibn Tulun’s, and the stylistic resemblance can be seen. In addition to these feats of grandeur, smaller, exquisitely built prayer places were springing up everywhere, such as the mosque of al-Aqmar, whose name means “moon-lit.” It was intended as a palace chapel for the private use of the caliph and his entourage, and as a culminating point for grand Fatimid processions.

Following the fall of the Fatimid dynasty with Salah al-Din’s (Saladin’s) conquest of Egypt in 1171, there came with the new ruler a new religious institution, the madrasa, which was equivalent to a private college. This Salah al-Din introduced to reeducate the population in the four schools of Sunni jurisprudence—Shafi’i, Maliki, Hanafi and Hanbali, named after the religious leaders who founded them. Whereas the mosques were open to all, the madrasas received only limited numbers of students. Gone now were the vast enclosures built to hold all the inhabitants of the city. The layout of the madrasa was centered around a much smaller courtyard, which was often surrounded on four sides by deep alcoves (iwans), one for each of the schools of jurisprudence.

About this time another institution, the khankah, was also introduced by Salah al-Din. First founded within the city walls, khankahs—meeting places of religious brotherhoods—soon flourished in the remoteness of the surrounding deserts, where the nobility had plenty of space to build lavishly.

At first madrasas and khankahs, even when provided with minarets, were not places of public worship. But by the Mamluk era, which began in 1250, they gradually came to be fused with the congregational mosques. Within the city, large madrasa-mosque complexes were built, complete with lodgings, lecture rooms, libraries, schools for orphans and practical services such as flour mills or a cistern with a waterwheel (sakia) to convey running water to the surrounding district.

The largest and most luxurious of these complexes was that of Sultan Hasan.

ive hundred years passed between Ibn Tulun’s construction of his mosque in the desert and the time when Sultan Hasan ibn Qala’un set out to build at the foot of Salah al-Din’s 12th-century citadel. Sultan Hasan’s grandfather, Mansur Qala’un, had already set the pace for building great mosques in 1284 with his madrasa and hospital in the heart of Cairo. Sultan Hasan’s father, Nasir Muhammad, who reigned for nearly 50 years, built an even vaster edifice within the walls of the citadel, capable of holding 5000 worshipers. It was during Nasir Muhammad’s long reign that it became the fashion for even minor nobility to build ever more splendid mosques, palaces and public drinking fountains (sabils).

Though he was born into an age of architectural splendor, Sultan Hasan’s years were strewn with intrigue and disaster. He only reached the throne after succeeding his seven brothers, each of whom briefly occupied it before being either murdered or deposed. First elected at the age of 11, then at 16 overthrown by one of his brothers and committed to the citadel’s infamous dungeon, he languished for three years before being released and made sultan again in 1354.

Sultan Hasan’s restoration coincided with a disaster: Bubonic plague, “the black death,” arrived in Cairo in the autumn of 1348. Within two years, 200,000 died in Cairo alone, and large parts of the city, the historian Maqrizi tells us, were depopulated.

Sultan Hasan, however, survived, and just as Ibn Tulun, in his day, had came into sudden wealth and used it to build grandly, Sultan Hasan, too, found himself suddenly in possession of enormous wealth from the estates of plague victims. He decided to use part of the money to build another great mosque. He is said to have asked for “something impressive,” as indeed he might well do if he were to stand a chance of surpassing his father’s and his grandfather’s colossal accomplishments.

Plans were developed for a vast mosque-madrasa complex with dormitories and accommodation for 500 teachers and students. A khankah which was to have been built in a second stage was never completed. Compared to Ibn Tulun’s sprawling and essentially horizontal desert grandeur of fired brick five hundred years before, Sultan Hasan’s madrasa-mosque was built out of huge blocks of stone in soaring vertical splendor.

Of unprecedented scale in the Islamic world, Sultan Hasan’s mosque became the culmination of all the architectural power developed throughout a century of Mamluk rule. An impressive flight of steps leads to an entrance portal of tremendous height, its peak decorated with a muqarnas ceiling of stalactites. A narrow, lofty, gradually ascending passageway follows, which emerges suddenly out of darkness into the blinding sunlight of a courtyard paved in patterned marble. The Egyptian architect Hasan Fathy described the experience: “Immediately, your eyes are drawn upward into the blue sky. And as you lower your head, ‘peace’ with Allah’s blessing of contentment descends upon you.”

And as you lower your head, your gaze spreads across the patterned mosaic-paved courtyard, unprecedented in the city. Soaring up from this expanse, four enormous vaulted iwans, or halls, shelter the four schools of Sunni Islamic teaching. The eastern iwan is the mosque’s sanctuary and the only one where the decoration begun by the Sultan was completed, with a splendid Kufic inscription, marble paneling on the qibla wall (the one indicating the direction of Makkah) and a dazzling, multi-colored marble mihrab. In Sultan Hasan’s day a multitude of the famous Mamluk enameled glass lamps, suspended on fine chains, glowed in the immensity of the mosque’s interior space.

The mosque was meant to have four high minarets, though today there are only two: One collapsed, killing some 400 orphans; the fourth was never built. In the sultan’s time, the mosque’s call to prayer was announced by a chorus of 60 muezzins working in two shifts who intoned from the door of the mosque, the courtyard, inside the sanctuary, from the roof and from the high balconies of what were then the city’s two tallest minarets. Unlike the bare mosque of today, in the 14th-century mosque rich carpets lay across the marble floors, while huge brass candlesticks illuminated the open pages of immense royal Qur’ans resting on carved wooden lecterns inlaid with ivory and mother-of-pearl. Nearby were silver water bowls and censers.

Alas, in 1361, just before the completion of his mosque, Sultan Hasan lost his throne, and possibly his head, in another palace coup. No one is quite sure what happened. Some say he escaped; others say he was tortured and that he died in the citadel’s dungeon. We know for certain he does not rest in the rich mausoleum he built for himself at the back of the mosque’s sanctuary.

The three Qala’uns—grandfather, father and son—gave to Cairo three most impressive mosques. Of them, Sultan Hasan’s is undoubtedly the most splendid. Nothing has ever surpassed it since. Six centuries after its completion, in the early 19th century, the architect Louis Sullivan was influenced by it in his design of New York’s first skyscrapers. In the late 1970’s, the United Nations Educational, Scientific and Cultural Organization (UNESCO) decreed Sultan Hasan’s great mosque a World Heritage Site. Sultan Hasan did, at least, get his heart’s desire: “Something impressive.”

Since the 1960s, John Feeney (NH.Phua@xtra.co.nz) has been one of Saudi Aramco World's most frequent contributors, and the architecture of Islamic Cairo remains one of his favorite subjects. John Feeney Retrospective: 40 Years of Photographing Egypt is on view at Cairo's Sony Gallery from March 7 through April 21.