Rampart and door in the Qasaba of the Udayas

A wall in the shape of an irregular pentagon surrounds the Qasaba of the Udayas. On the Bou Regreg oued (river or Wadi) side, it follows the twists and turns of the cliff that overhangs it, and only a few fragments of the wall are still standing. The courses on the other sides—those next to the ocean and the land—are more extensive and better preserved. The enclosure is composed of four walls of varying heights that are different and perpendicular to each other. The walls in rough-hewn masonry arranged on regular beds sit directly on the rock or on a stone base. They are wide enough to contain a perimeter walk protected by a parapet pierced with loop-holes and crowned with pyramidal merlons. These ramparts are flanked with oblong chamfered or semi-circular towers that connect to the walls or in the corners, in accordance with Moroccan-Andalusian traditions. These works have solid bases with defensive rooms on the upper level.

The Udayas Qasaba has a sturdy and imposing perimeter, and great military value. The fortress is typical of the Almoravid tradition; this applies to the materials and construction techniques, all of which show the influence of Almoravid architecture.

The so-called Bāb al-Kabīr door is one of the finest examples of Almohad architecture. It is level with the exterior of the qasaba’s enclosure; it leads onto the square of the former suq Leghzel and dominates the medina of Rabat with its position. Two sturdy projecting towers flank this imposing ensemble. One enters through a monumental bent door composed of three adjoining rooms. The opening has a pointed arch. This door leads to a small rectangular hallway: a second similar arch provides access to the first room with its dome on squinches, which are voussoirs that straddle the corners. Three steps lead into a second room covered with a dome on pendentives. A small hall leads inside the Qasaba through a bay with a pointed arch—flanked by two anta—whose proportions are slightly different from the first. Five steps finally lead to the third room covered with a transversal barrel vault. In the western corner of the room, a small vaulted passage leads to a stairway that leads to the terrace and the first floor. This is dominated by the extrados of the vaults and domes, and arranged in corridors that communicate, on the north side only, with the perimeter walk.

Its stone-carved decorations are geometric and floral in design. The lines are simple and emphasize the friezes and bands, while the floral motifs are wonderfully rich shapes and combinations. All the classic elements of Almohad architecture are present here. The bases of the arches are engraved with serpentine patterns that are prolonged towards the top by voussoirs with festooned arches. The spandrels are clearly marked by scallops adorned with a floral decoration of stems and single and double palm leaves. An epigraphic band in kufic script frames classical architectural knotwork. The ensemble is crowned with a frieze of blind arches bordered with richly decorated consoles.

Despite its sturdiness and imposing appearance, this door was not intended to have a defensive role. Some believe it to be the door of the Almohad palace, whose spacious halls were used for tribunals and receptions.