The site described here was referred to locally as Lisan al-Arz in the early seventies when E. Galdieri surveyed and made drawings of its ancient remains. It was located off the road leading from Pul-i Khwaju to the airport on the south side of town, adjacent from a cemetery known as Takht-i Fulad (or Takht-i Pulad). At the time of the survey, it consisted of a clearing, roughly oriented along a northwest-southeast axis that contained a group of archaeological remains from at least three historical periods, possibly stretching back to the mid tenth century. The surrounding area had become a growing neighborhood that threatened to overtake the site, and parts of the enclosure were being used as a cemetery.
The oldest archaeological remains consisted of part of a large, mud-brick wall running along the southwestern side of the enclosure and the remnants of nine large piers in two rows parallel to this wall toward the western corner. Added to this at a later date was masonry constructed of baked brick abutting the aforementioned southwestern enclosure wall. This masonry included engaged pillars that framed niches along the wall. Finally, an iwan-structure was built toward the center of the wall and a structure at the center of the enclosure. This structure at the center of the enclosure was known as the "khanaqah" or "takkiyya."
Based on these findings, Galdieri concluded that the enclosure was built as a musalla (مصلى), or an open area for prayer, with a retaining wall and two arcades running parallel to it, of which the piers are the remnants. Based on the traces of carved stucco decoration on the piers, this first phase could date as early as the mid tenth century (fourth century AH). At a later date, possibly during the Seljuk Period, baked brick masonry was added. The mihrab iwan and the so-called "khanaqah" date much later, to the seventeenth or eighteenth century.
Sources:
Eugenio Galdieri, "A Hitherto Unreported Architectural Complex at Iṣfahān in the so-called ‘Lisān al-‘arẓ.’ Preliminary
Report.” East and West 23 (1973): 249-264.
Barbara Finster, Frühe iranische Moscheen. Berlin: Dietrich Reimer, 1994. p. 47.
Golombek 1974 Field Notebook, p. 40. Isfahan Urban History Project Archive, The Aga Khan Documentation Center, MIT Libraries.