Now only an imposing brick ruin, Ayvan-e Kasra is the most famous of all Sasanian monuments and a landmark in the history of architecture. While actually belonging to the city of Asbanbar on the east bank of the Tigris below Baghdad, the Ayvan-e Kasra was the legendary throne hall of the Sasanian kings. Construction began during the reign of Khosrau I after a campaign against the Byzantines in 540 CE.

Also called Ayvan-e Mada'en or Taq-a Kasra, the standing monument consists of a large portico (ayvan) 43.50m deep by 25.50m wide, penetrating a blind facade that stretches 46 m in either direction from the center line of the ayvan and stood originally 35 m above ground level to the height of its cornice. The articulation of the blind-facade is formed by a series of six stories of brickwork, consisting of columns, entablatures, and arched niches. The ayvan is roofed by a parabolic vault, with the side-walls tapering from 7 m to 4 m and brought forward by slight corbelling below the impost in order to reduce the enormous width to be spanned. The true part of the vault, for which slanting lays of brick on edge were employed (permitting the construction of a vault without centering), is confined to the upper third of the structure; this arch tapers from 1.80 m at the point of the spring line to 1.30 m at the crown. 

 

The great arch dominates the layout, but the area behind the facade can be shown to be taken up by a pair of large rectangular and square chambers on either side (if one can assume symmetry of plan) which are separated from the axial ayvan by a vaulted corridor system. Access to the corridor is gained through a doorway which penetrates the facade. Behind the ayvan, and connected to it by a narrow door, is an arrangement of rooms which are remarkable for their comparatively small dimensions. Through a cross passage and the central chamber one can enter the large hall at the rear of the complex. It is a later addition and measures 26 m wide by 38 m deep.

 In the course of history the great arch and its facade have aroused comments that generally have acknowledged its impressive qualities. Ebn al-Faqih considered it to be one of the marvels of the world. Tabari reports that the caliph al-Mansur was advised by his Persian minister Khaled b. Barmak not to attempt its demolition. This advice reflects both the building's prodigious dimensions and its reputation as a monument. In spite, however, of the past and present notoriety surrounding the Ayvan-e Kasra, including the observations of Muslim geographers, the accounts of travelers, and the attention of archeologists, it is still only largely circumstantial evidence which permits investigators to propose a specific date for the building's construction. That such a problem is a crucial issue stems from the fact that any interpretation of the building's significance in the history of architecture depends entirely upon knowing when it was built.

 

Recent probes, however, by the Italian Mission around the footings of Ayvan-e Kasra designed specifically as studies to plan the restoration of the monument-have demonstrated fairly strongly that there is no archeological evidence for such suggested refurbishing. The Mission reports that the only major changes visible from the probes appear to have occurred after the tearing-out of the precious wall facings (presumably after the Moslem conquest). It would be surprising if all traces of earlier phases had been completely removed, even if the hypothetical sixth-century refacing had involved the complete removal of the earlier pavements. Virtually no finds were recovered from the fill associated with the footings which could in any way provide a satisfactory date, although the universally problematic greenish-blue glazed pottery was found in the upper layers and assigned "a definite early Islamic."

 

The recent restoration projects on the Ayvan-e Kasra itself seem to imply that no further refinement of this date will be possible using conventional stratigraphic excavation techniques, unless some of the small side and rear chambers can be safely excavated, with the chance that more diagnostic dating material can be found in them. Excavations in the general area will advance considerably our knowledge of the history of Mada'en, but barring a laboratory breakthrough for the dating of its bricks, the date and therefore significance of the great arch is likely to remain somewhat elusive.

 Ayvan-e Kasra has been mentioned and often described in Arabic and Persian sources and it is the subject of a moving Qasida by the Persian poet Khaqani who visited its ruins in mid-12th century.

(Source: cais-soas.com)