The Palace of the Golden Gate (Arabic: قصر باب الذهب, romanized: Qasr Bāb al-Dhahab) or Palace of the Green Dome (Arabic: قصر القبة الخضراء, romanized: Qasr al-Qubbat al-Khaḍrāʾ) was the official caliphal residence in Baghdad during the early Abbasid Caliphate.
Baghdad was founded in 762 by the second Abbasid caliph, al-Mansur (r. 754–775). The main part of the original city was the Round City, with the Palace of the Golden Gate and the adjacent Great Mosque of al-Mansur at its centre.[1] Apart from the mosque, no other buildings were allowed to be built close to the palace, which was thus surrounded by a wide open space; only on the northwest, towards the Gate of Syria, two buildings were constructed next to the palace wall: a barracks for the caliph's horse guard, and a two-part gallery, originally intended as an audience hall for the sahib al-shurta (police chief) and the captain of the horse guard respectively, but later came to be used as a public prayer space.[2] Around this space, the palaces of al-Mansur's younger children, quarters for the palace servants, and the offices of the various administrative departments were built.[3]
The palace originally occupied an area of 200 square yards (170 m2), with a central building topped by a green dome, 48.36 metres (158.7 ft) high, which gave the palace its alternative name of al-Qubbat al-Khadra'.[3][4] At the top of the dome was the effigy of a horseman carrying a lance, who in later times was credited with magical properties: he would allegedly turn his lance towards the direction where enemies were approaching from.[3] Underneath the dome was a square audience chamber 30 feet (9.1 m), with a vaulted ceiling just as high; and above that, in the interior of the dome, was another chamber of similar dimensions.[5] In front of the audience chamber was an alcove, called the aywan, which was surmounted by an arch 45 feet (14 m) high and 30 feet (9.1 m) wide.[5]
The palace and mosque appear to have been completed in 763, one year after construction began, allowing al-Mansur to take up residence in the city.[4] While the Palace of the Golden Gate remained the official residence of the caliphs, al-Mansur and his successors also spent much time in the nearby Khuld Palace constructed soon afterwards.[5] Caliph Harun al-Rashid (r. 786–809) is said to have particularly preferred Khuld over the older palace, but his son al-Amin (r. 809–813) restored it as his residence, added a new wing to it, as well as a large square (maydan).[4][5] As the main stronghold of al-Amin and his partisans, it suffered extensive damage from bombardment by catapult during the Siege of Baghdad (812–813). The palace then ceased to be used as a royal residence, and became neglected.[4][6]
The palace remained intact, although part of the structure was torn down to facilitate the expansion of the nearby Great Mosque under al-Mu'tadid (r. 892–902). The landmark Green Dome remained standing until the night of 9 March 941 (7/8 Jumada II 329 AH), when heavy rainfalls, and possibly a thunderbolt strike, led to its collapse.[4][7] The walls of the dome survived until the Sack of Baghdad by the Mongols in 1258.[4]