Within the Citadel of Aleppo lie the ruins of a monumental portal and palatine structure immediately behind it attributed to the patronage of the Ayyubid sultan al-Malik al-Zahir Ghazi (r. in Aleppo from 1188-1216/ 582-613 AH). This ruin was originally attributed by Ernst Herzfeld to al-Malik al-Zahir's son al-Malik al-Aziz,1 but literary and archaeological evidence have encouraged more recent scholars to revise this theory, identifying the remains of the portal and the structure behind it as the patronage of al-Malik al-Zahir and the adjacent ruins to the south as having been the patronage of his son. Medieval authors suggest that al-Malik al-Zahir referred to his palace as Dar al-Shukhus (Abode of Figures or Abode of Images) due to the presence of wall paintings, and that the structure was built to replace a previous palace that burned named Dar al-'Izz (Abode of Glory).2

The palace occupied approximately two-thirds of a rectangular block measuring circa 40 x 45 meters that also includes ruins of a bath house and part of an arsenal. It lies to the east of the path leading from the citadel's Entrance Block to its Great Mosque. The entrance to the palace is through a monumental portal in the form of a recessed niche vaulted with muqarnas, framed with ablaq stripes and surmounted by a geometric frieze based on a star pattern. Within the niche, the doorway is framed by joggled stones in alternating black and white carved with a geometric pattern.

The portal gives onto an ample rectangular vestibule where visitors would turn left and proceed through a passageway leading onto a long corridor following the western and northern periphery of the building: this corridor first follows the western wall of the complex to its end, then turns at a right angle to follow the northern wall, then turns again at a right angle southward into the heart of the building to give onto a large internal courtyard. 

The large internal courtyard at the end of the peripheral corridor was once paved and features an octagonal fountain at its center. It is based on a cruciform plan with an iwan on each of its sides, the south iwan being by far the largest and connecting to the arsenal buildings on the south side of the complex. The iwan on its north side is also distinguished by its depth and the presence of a niche with muqarnas vault at its rear which once contained a fountain. This iwan may have been used as a frame for the patron during receptions, its niche fountain providing a splashy backdrop for the seated ruler.3

A second, smaller courtyard also based on a cruciform plan is located just east of the large courtyard complex. It has iwans on three sides: east, north and west, with the northern iwan being the largest. On the southern side, a three-arched portico gives onto a corridor connecting the small courtyard to both the peripheral corridor (to its east), and the large courtyard (to its west).

Sources:

Allen, Terry. Ayyubid Architecture. Occidental, CA: Solipsist Press, 1999. http://www.sonic.net/~tallen/palmtree/ayyarch/ 

Herzfeld, Ernst. Matériaux pour un Corpus inscriptionum arabicarum. Part 2: Syrie du nord. Inscriptions et monuments d’Alep, vol. 1, pt. 1, pp. 137-139. 2 vols. in 3 parts. Cairo: Institut Francais d'archéologie orientale, 1954-1956. 

Tabbaa, Yasser. Constructions of Power and Piety in Medieval Aleppo. University Park, PA: Pennsylvania State University Press, 1997.