The Aljafería Palace is a fortified palace built in the second half of the 11th century on the initiative of al-Muqtadir as the residence of the Hudid kings of Saraqsta. This pleasure palace was then called Qasr al-Sur or 'Palace of Joy' and reflects the splendour achieved by the Taifa kingdom at the height of its political and cultural splendour.

Its importance lies in the fact that it is the only surviving evidence of a large building of Hispano-Muslim art from the Taifa period. Thus, if a magnificent example of the Caliphate of Córdoba, its mosque (10th century), and another of the swansong of Islamic culture in al-Andalus, the 14th-century Alhambra in Granada, have been preserved, the Aljafería Palace in Zaragoza (11th century) must be included in the triad of Hispano-Muslim architecture as an example of the achievements of Taifa art, an intermediate period of independent kingdoms prior to the arrival of the Almoravids. The 'Mudéjar remains of the Aljafería Palace' were individually declared a World Heritage Site by UNESCO in 1986 as part of the 'Mudéjar Architecture of Aragon' ensemble.

The solutions adopted in the ornamentation of the Aljafería Palace, such as the use of mixtilinear arches and 'S'-shaped salmeres, the extension of openwork ataurique over large surfaces and the gradual schematisation and abstraction of vegetal plasterwork, had a decisive influence on Almoravid and Almohad art in both the Maghreb and the Iberian Peninsula. Likewise, the transition of decoration towards more geometric motifs is at the basis of Nasrid art.

After the conquest of Saragossa in 1118 by Alfonso I the Battler, it became the residence of the Christian kings of Aragon, making the Aljafería the main centre for the diffusion of Aragonese Mudéjar art. It was used as a royal residence by Peter IV the Ceremonious (1319-1387) and later, on the main floor, the rooms were converted into the palace of the Catholic Monarchs in 1492. In 1593 it underwent another reform that converted it into a military fortress, first according to Renaissance designs (which can still be seen today in its surroundings, moat and gardens) and later as a barracks for military regiments. It underwent continuous alterations and suffered major damage, especially during the Sieges of Saragossa during the War of Independence, until it was finally restored in the second half of the 20th century and now houses the Aragonese Parliament.

It was originally built outside the walls of the Roman wall, on the plain of the saría or place where the Muslims held their military displays, known as La Almozara. With urban expansion over the years, the building has remained within the city. A small garden area has been preserved around it.