This ruined funerary complex is located in the village of Kuhsan, ten kilometers east of the Iranian border on the Herat-Mashad road. Its early identification by Nicolai Khanykov as the funerary madrasa of Tuman Aqa (sixth wife of Timur, 1366-144?) was rejected in 1968 by G.A. Pugachenkova, based partially on the monument's local attribution to Gawhar Shad (first wife of Shah Rukh bin Timur), otherwise thought to be buried in her madrasa in Herat. Recent work by Bernard O'Kane confirms that the complex was commissioned by Tuman Aqa during her retirement years in Kuhsan. The domed burial chamber and prayer hall remaining today are thought to be part of a two or four-iwan madrasa, whose date of completion 1440-41 (844 A.H.) is inscribed in small Kufic script on the cuerda seca tiles of the dome's drum. It is not certain whether the queen was buried here or in her eponymous khanqah at the Shah-i Zindah Complex (Samarkand) after her death. Remains of a caravanserai or ribat, also built by Tuman Aqa, are located northwest of Kuhsan.
The complex, as it stands today, consists of an octagonal dome chamber and a rectangular hall to its southwest, joined by a small domed vestibule in between. A deep iwan with a collapsed vault and portal screen precedes the dome chamber; this was the southern iwan of the madrasa courtyard. Fragments of the chamfered corner of the courtyard stand immediately to the left of the iwan, housing two doorways leading into the domed vestibule. Now known as the ziarat-khanah, the vestibule measures about six meters per side and has survived in poor condition with a partially collapsed dome. A doorway on the west wall of the ziarat-khanah leads into the rectangular hall. The hall measures is about six and a half meters wide and thirteen meters long (north-south) on the interior and is also entered from the north and south. Its vaulted roof and central dome are supported on five transverse archways, two of which are embedded into the north and south walls. A mihrab carved into its western hall shows that it was used as a prayer hall (masjid).
The octagonal dome chamber measures about fourteen meters wide on the exterior and eight meters on the interior. It is covered with a double-dome resting on eight heavy piers located at the corners of the octagon; these piers are connected with vaults and relatively thin walls, creating deep arched niches on the inside and shallower niches on the outside. The three southern niches have doors leading into the chamber from the ziarat-khanah, the southern iwan, and a small room accessed from the madrasa courtyard. A fourth doorway is located inside the northern niche, while the east and west niches are pierced only with arched windows.
The interior of the dome chamber is adorned with squinch-net compositions on the niche vaults and the dome, which are filled in with muqarnas carvings and highlighted with painted arabesques. The squinch-net vaulting of the dome begins with a circular belt above the niche arches, transitioning from sixteen crossed archways to a thirty-two pointed star; the star is ringed with rows of plaster muqarnas raising the center of the dome for depth effect. Only a single inscription, verses from 'Imran sura in thuluth script, can be seen inside the niche leading out to the iwan. The neighboring ziarat-khanah is also adorned with squinch-net vaulting and painted arabesques.
The madrasa is built of bricks above a marble foundation course. The dome of the mausoleum, which is raised on octagonal and cylindrical drums, dominates the exterior; a tiled ring of muqarnas distinguishes the squat dome from its drum. Surfaces of the dome and the drum were originally covered with tile mosaic and cuerda seca tiles featuring inscriptions and floral and geometric motifs. Remaining segments of the large nakshi script on the drum and smaller kufic inscriptions fitted in between were read by O'Kane, and contain the date of completion. Tile mosaics with diamond and cross motifs cover the five exterior walls of the dome chamber, while remnants of a wide inscriptive band in tile mosaic can be observed inside the collapsed southern iwan.
Golombek, Lisa, and Donald Wilber. The Timurid Architecture of Iran and Turan, 325-27. Princeton, NJ: Princeton University Press, 1988.
Khanykov, Nikolai. "Lettre à M. Reinaud" Journal Asiatique 5th ser., no.15 (1860): 537-43.
O'Kane, Bernard. Timurid Architecture in Khurasan, 197-201. Costa Mesa, California: Mazda Publishers, 1987.
Pugachenkova, G. A. "Les Monuments Peu Connus de l'Architecture Médiévale de l'Afghanistan." Afghanistan 21/1 (1968): 27-41.