In the second half of the 11th century, Abu Jafar Ahmad I ibn Suleiman al-Muqtadir billah (1049/1050-1082/1083), second ruler of the Banu Houd dynasty, built the Aljaferia of Saragossa. The Aljaferia, named after him (derived from the Arabian name "Jafar"), is the most important Taifa period Palace complex and has survived almost intact. In 1118, King Alfonso I of Aragon re-conquered Saragossa and immediately chose the city as his kingdom's capital. In succeeding centuries, kings of Aragon continued to use the Aljaferia as a state residence, and frequently remodeled it - following the contemporary taste.
 

The Aljaferia is a trapezoid, nearly square complex, its sides measuring about 80 meters (260 feet), and outer walls are interspersed by round towers. Inside the enclosure are three sections running north-south in an axially symmetrical way, with only the central zone built upon. This constitutes the palace area proper, in the center of which is a large, rectangular courtyard, bordered on its two narrow sides by building complexes called the palace's northern and southern wings.


The southern wing comprises a long hall (the South Hall), outside stands portico, whose arcade comprises six wide spanned, interlaced semicircular arches with uniquely ornamented faces. The ornamentation is constructed from a repeated framing of the basic elements forming the arches, and is typical Taifa period innovation.. A striking feature of this portico is the arcade consisting of six large, interlacing similar to Medina al-Zahra's reception halls. These days there is a basin in the first hall of the northern wing of the palace, installed during a later Christian extension. Formerly, its surface reflected the arcade of the adjoining northern portico, whose massive, interlacing multifold arches recall comparable arches in the Great Mosque of Cordoba.


Through the portico one can look at the magnificent access arcade of the adjoining main room (the northern hall), called the Golden Hall, or the Throne Room. Today, hardly any of its original architectural decoration survives. The Throne Room's central position on the castle's main axis, the graduation of both preceding halls, and its design also suggest that this has always been the palace's most important location.
 

The Aljaferia also contains a small palace mosque, located in the eastern side section of the northern palace wing, and can easily be found within the Aljaferia complex because of its octagonal ground plan. Inside the small mosque, the dome is about 10 meters (33 feet) high, is remarkable for its highly ornate stucco decoration, extending along the walls on either side of the mihrab.
 

The stucco plant designs show the caliphate's influence, even though the leaf tendrils are now smaller, slimmer, and more finely segmented. The leaf stems also reveal a strong tendency to roll up, which helps establish the rhythm and articulation of the plant decoration - both features that are very typical of Taifa architecture.