The inscriptions of the complex give the construction dates of the two main buildings, the names of the founders, and the artists. The mosque was constructed during the reign of the Seljuk Sultan Alâeddin Keykubad I by the order of the Mengücek prince Ahmed Şah whereas the construction of the Hospital was begun by the order of Turan Melek Şah, the daughter of Fahreddin Behramşah, both built in 1228-29 by the architect Hürremşah of Ahlat. From the inscription on the pulpit dating to 1240-41 and giving the name of the founder, we can assume that the construction continued up to this date. Other artists were responsible for the east window (originally the portal of the sultan's loge; decorator Ahmed of Ahlat), pulpit (Ahmed of Tiflis) and the painted decoration inside the mosque (Ahmed, the son of Mehmed). The complex of the Great Mosque and Hospital, with its five artist inscriptions, is a very important example amongst the Seljuk monuments, which usually bear only one or two inscriptions indicating the names of the artists. It also brings to light a very significant problem concerning the team-work of artists conducted during the Seljuk period, which unfortunately can only be traced from inscriptions and rare literary sources.

The mosque has a longitudinal plan in its north-south axis. Besides the portals on the north and west facades, there is a monumental window on the southern part of the east facade which was originally the portal opening to the sultan's loge, and was later replaced by a window. Twelve octagonal piers in two rows with pointed arches divide the interior into twenty-five bays. The largest section in front of the Mihrab is covered with a ribbed dome borne on Squinches, whereas the central unit is covered by a dome with an oculus. Both domes have octagonal drums expressed externally. The five domes of the west section are not original but are assumed to have been altered from vaults during restorations. The remaining spaces are covered with a highly inventive system of ribbed vaults. One of these covers the original sultan's loge. This building is one of the few significant examples bearing the original sultan's loge from the Seljuk period.

Traces of red, white and some green paint can still be observed on the mihrab dome, transitional elements, vaults and the beams of the sultan's loge. The original painted brushwork of this building is one of the rare surviving examples amongst Seljuk monuments. The cut-stone Mihrab has a semi-circular niche and the half-dome covering the niche is decorated with scrollwork’s and vegetal floral patterns partly in high-relief. The pulpit located to the western part of the Mihrab is built of timber and represents one of the best examples amongst Seljuk timber-work pulpits with its geometric interlace. Especially the vaults are decorated with floral and geometric interlaces mostly distributed freely.

Although the interior is highly decorative, the most remarkable elements of the mosque are the portals on north and west facades as well as the monumental window on the east facade. Besides these elements entirely dominant to the building with their size, structure and decoration, the facades are very plain.

The impressive north portal is named "Baroque portal" by the scholars for its incomparable, partly high-relief splendid floral and geometric interlaces. Palmettes in vases are also seen. The most remarkable feature of the portal amongst the other examples of the Seljuk period is not merely the high-relief interlaces or floral motives projecting from the surface, but also the decoration unlimited within the defined outlines of the framework as observed on most Seljuk portals. On the contrary, most of the decorative elements, especially the floral ones are freely distributed on the surface.

The west portal, compared with the north one is less monumental and bears more superficial decoration. The decorative elements, limited within the defined outlines of the bands and niches composing of floral and geometric patterns covering the whole surface reminds textile-work and is called "Textile portal" by the scholars. In addition the stalactite niches on both sides of the portal are decorated with figural representations. On the north there are single and double-headed eagles, whereas on the south only a double-headed eagle can be observed. The single-headed eagle is said to symbolize the founder and the double-headed one the Seljuk Sovereign, most probably the Sultan Alâeddin Keykubad I.

The east window, originally a portal opening to the sultan's loge was later replaced by a window. The stalactite portal niche with a pointed arch is surrounded from each side by two bands adorned with floral and geometric interlaces respectively. The structure and decoration of this portal bears many characteristic features common in most of the monumental portals from the Seljuk period and is called the "Seljuk portal" by scholars.

The buildings of the complex have been restored several times from the 16th century up to the present. These restorations were mostly carried out on the west facade, east portal and the interiors. However the basic scheme and decoration do not appear to have been greatly modified. The minaret at the north-west corner of the mosque is not original. According to the inscription on the shaft, it was constructed in 1565 by order of the Ottoman Sultan Suleyman the Magnificent.

In 1985 UNESCO declared this site one of the world's most important cultural heritages.

Palmettes stylized fanlike motif resembling the cross section of a lotus flower. It appears in both the field and border designs.