Building large new cities was the major architectural activity of the Abbasid caliphs. In terms of Function, these cities were logical successors to the garrison cities that the Umayyad had built in newly conquered regions. In terms of architecture, however, these new cities were the continuation of a long Mesopotamian and Iranian tradition of rulers building administrative capitals

These range from Durr Sharruhin, the city founded by the Assyrian ruler Sargon 11 (721-705 northwest of Mosul at Khorsabad, to the round city founded by the Sassanian emperor Ardashir I (224-241) at Gur (modern Firuzabad) in the province of Fars in Southwest Iran.

During the first decade of Abbasid rule, the caliphs erected several administrative centers in the vicinity of Kufa, in southern Iraq. They were known as al-Hashimiya (in reference to the family from which both the Prophet and the Abbasids descended), but nothing remains of them and the sources provide little additional information. These centers must have been royal residences, since at least one of them had a throne room, called a khadra, the same word that had been used in the Umayyad period for a throne room.
 

The Abbasid throne room was on an upper floor, for the 0th century historian al-Tabari reported that, when the Rawandiya rebels, members of an extremist Shiite sect, approached Caliph al-Mansur (754-775) in his khadra, they attempted to escape out the window and fell to their deaths. Al-Tabari's report indicates that even the earliest Abbasid administrative centers were substantial multistory buildings.

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Stucco decoration from room four in house one in Samarra - Berlin, Museum of Islamic Art.

The mud brick buildings constructed in Samarra were frequently decorated with stucco relief's. The artisans developed three different styles, differentiated by the level of stylization of the vegetal motifs. The decoration of this panel exemplifies the Samarra style, in which the field is divided by decorated bands into compartments, here hexagonal, which contain recognizable leaves growing from vines. The leaves often have four (eyes) and veins.