Although it is prone to be presumed that Cairo, the capital of Egypt, has been there since the time of ancient Egyptian civilization, actually it was constructed far later, in 969 as an Islamic city named �eal-Qahira�f (the Victorious).
It holds so many heritage sights that it is called a 'treasure house of Islamic architecture.' The oldest mosque among them, the Amr Mosque, is in fact older than the establishment of al-Qahira and is located in the southern part of Cairo, now called �eOld Cairo.�f

It was in 640 that the Muslim army conquered Egypt and the Muslim general Amr ibn al-As constructed a military capital (Misr) designated as 'al-Fustat' to govern the territory. It was the following year that the Amr Mosque was built there, the name of which was derived from his name.
The neighboring site to the Fustat was the still older Babylon, the citadel constructed in 96 in the Roman era, holding ancient Christian churches and monasteries still now. The whole area is called Old Cairo nowadays.

Windows on the wall of the Amr Mossque

Even though the Amr Mosque is the oldest mosque in Egypt, it doesn�ft retain the original building. According to a record, the mosque erected by Amr was as small as 29m x 17m without a minaret, a mihrab, nor a courtyard that would become common features for mosques.
The erection of the Amr Mosque was only 30 years after the Prophet Muhammad had received the revelation from God for the first time in around 610, so the architectural form of mosques had not been established yet. The mosque must have been the simplest building in teh desert area, making the trunks of date palm stand as columns, enclosed with sun-dried brick walls, and covered by a roof of mud and palm leaves, like the earliest mosques built in Arabia, Syria, and Iraq of that age.

The origin of a mosque can be traced back to the house of Muhammad who came to Madina to avoid the persecution in Makka in 622. It was a large square site (courtyard) surrounded with walls.
Since the followers worshipped in the early days to the direction of Jerusalem, which was the holy place for Judaism and Christianity that Muhammad considered as the sibling religions with Islam, they made shadows for the daily worship space at the Jerusalem side (the north side) of the courtyard, covered with a roof made with trunks and leaves of date palms.

However, as the confrontation with the preceding religions gradually augmented, Muhammad changed the direction of worship (Qibla) 180 degrees to the direction of the Kaaba in Makka. As they made shadows at the Makka side (the south side) this time, the courtyard of Muhammad�fs house became an oblong space surrounded with galleries with flat roofs.

Courtyard of the Amr Mosque

It was treated as the model of mosques to be erected in various regions, adding a �eMihrab�f to the center of the Kibla wall in the form of a niche, which indicated the direction of Makka, and a fountain in the center of the courtyard, with which followers washed their hands and feet before worship. It grew into the �eArabian type�f mosque.
It was in 673, thirty-two years after establishment, that the Amr Mosque took such form and furthermore added the first �eMinaret,�f a tower from which to call devotees to come for worship. The current round minaret is the later one built in the Turkish era; the former one might have been the square-type imitating Christian bell towers.

Plan of the Amr Mosque, 827
(From " Architecture of the Islamic World" by George Michell (ed.), 1978)

Since it was enlarged and rebuilt many times, the extant figure of this grand mosque of 120m x 110m is the result of a long historical vicissitude. Even so, it still retains the features of the earliest Arabian type mosque.
First of all, the worship room is a flat roofed hypostyle hall; a forest-like space with dense columns taken from ancient Roman temples or Christian churches with continuous arches above.

 
Interior of the worship room, Amr Mosque

As what Muhammad wanted was buildings consisting of utilities and structural necessities without ostentation, that is to say, functionalist architecture; the external appearance of a mosque did not have a sculptural figure symbolically. It was just intended to provide a shaded space for worship in the direction of Makka.
If the formation of such a non-monumental religious architecture is caused by the �erejection of idolatry-like factors,�f the Arabian type mosque might be an exemplary result of the accord of faith and architecture.

However, architecture does not come into existence solely by religious passion. Without the elaborate design and steady building skill, a building cannot endure long years. The reason that the Amr Mosque had to be reconstructed many times was that it was devastated by its arches distorting and columns leaning every few decades.
It was unreasonable from the beginning to construct a large building by putting simply continuous arches across these hundreds of columns. Without tough walls or strong pillars at proper positions, this method makes it difficult to resist earthquakes and to restrain the thrust, which tend to flatten out the arches toward final collapse.
Finally, in order to cope with this weakness, they added stability by joining the tops of all the columns in the mosque reciprocally with thin timber beams, so it could not continue as a pure stone building.

(In "Chugai Nippo" 2004)