|As you enter the mosque by the South Eastern entrance you are plunged into a series of cloisters which are punctuated by open and closed vaults giving strong contrasts between light and dark and imposing a need for spatial and ocular re-adjustment. As your eye becomes accustomed to these changes the diversity and intricacy of the cloistered space becomes apparent. Everywhere there is a different vista, as shown by the illustration above. As in "The Garden of Cyrus", there are quincunces in every direction - wherever you look there are lines of pillars, some with curious markings on, as in the example above. Here we find a magnificent example of the "mystical mathematics of the City of Heaven" of which
Sir Thomas Browne wrote.
The mystical mathematics were well known to the Sufi craftsmen who designed this part of the mosque. Their system of mathematics was called abjad, and provided a conceptual springboard from which the diverse and inventive geometrical patterns in the roof vaults were derived. Originally it was probably a huge library, and this hypothesis is borne out by the presence of lampholders in part of the cloisters, but after the siege of Isfahan by Toghril Begh, during which large parts of the mosque were ransacked to provide winter fuel, it was rebuilt in its present form. Reconstruction is still taking place - extensive damage was suffered in this part of the mosque during the Iran-Iraq war.
It was amongst these strange cloisters that one of the greatest Iranians of all time, Nizam al-Mulk, the vizier of Malek Shah and friend and patron of Omar Khayyam, chose to erect his prayer chamber.