Dar Mustapha Pasha is a palace located in the section of the Casbah, where all the great ottoman palaces and mosques were located. It is one of the rare palaces that did not undergo major transformations during the French occupation. It is thus the best preserved palace of the Casbah and one of the largest, giving a precise idea of the palatial architecture of that time. Its construction began in 1798 on orders of Mustapha Pasha, Dey of Algiers. It was completed in 1799-1800/1214 AH.
The main entrance opens onto a series of three skifat (sing., skifa; vaulted vestibules). The second is the main and the largest. It is bordered with dukkanat (sing., dukkana; masonry bench seats) which are themselves surmounted by Algiers-style arches resting on wreathed double columns. The bottom of the niches is decorated with zellij. The third vestibule gives access to a large central courtyard (wust ad-dar) centered by an octagonal fountain.
The courtyard has two levels of arched galleries, surrounding it on its four sides. Each gallery side has four pointed horseshoe arches, maintained by wooden rods, and resting on columns, wreathed on their upper halves. All column capitals of the courtyard are composite and decorated with crescent shapes between the two volutes.
On the second floor, the galleries give access to large alcove rooms, which the doors are not axial to the courtyard. On the north side, there is a door giving access to the dwira (small annex house) which is the servants' apartment. It has a large kitchen centered on a small patio. The third level contains a kind of belvedere from which one can contemplate the Mediterranean Sea.
The floor of the palace is paved with marble hexagon tiles, unlike the lower part walls which are covered with a zellij. The woodwork of the doors is quite similar to those of Dar Aziza. However, the Algiers-style arches are much more abundant and elaborate in Dar Mustapha Pasha. They can be found in almost all wall niches, whether in the skifat, stairs, or rooms.
During the French occupation, and more precisely in 1863, the palace became a library-museum. After Algeria's independence in 1962, it housed administrative offices until 2007 when it was established as the National Museum of Illuminated manuscript and Calligraphy.
In 1887, the palace was listed as a historic monument; and in 1992, it was listed as a UNESCO World Heritage Site, as being part of the Casbah.