Orient the prayer hall so that its principal wall, the qibla wall, stands square to the direction of Mecca, and mark the middle of that wall with a niche, the mihrab.
qibla wall ⟂ direction of the Kaaba; mihrab on the axis
The centre kept empty for palace and mosque
Leave the centre of the city open: set the palace and the congregational mosque side by side in a great court, and allow round its edge only the guard, the police and the offices of state: no private houses and no markets.
palace 400 × 400 cubits; mosque 200 × 200 cubits; Green Dome 80 cubits high
At the centre of the Round City stood the palace of the Golden Gate, crowned by the Green Dome over its audience hall, and against it the Friday mosque. This was the pairing of the governor’s residence and the mosque already made at Kufa, Basra and Wasit, where the palace stood behind the qibla wall. Round the court were the guard, the chief of police, the treasury and arsenal, the offices (diwans) of government, and the houses of the caliph’s younger children.
Because the mosque was laid out square to the palace, its qibla did not point exactly to Mecca, and later writers noted that it had to be corrected. The empty court expressed the distance between the ruler and the ruled; in practice it lasted barely a generation.
Related rules
Build the congregational mosque as an enclosed courtyard (sahn) with a covered prayer hall (haram) on its qibla side and shaded porticoes (riwaq) on the others.
Make the prayer hall of identical bays of columns and arcades, so that it can be enlarged by adding aisles or bays without changing its character.
hall = n aisles × m bays of one module
Build the tower for the call to prayer in the form of the regional tradition: square and stepped in the Maghreb and Spain, cylindrical and tapering in Iran and Central Asia, needle-like and polygonal in the Ottoman lands.
Lay out the capital as a circle with four gates at equal intervals, each facing the region its road leads to, and put the ruler’s palace at the centre, so that no part of the city is further from him than any other.
4 gates on the diagonals (Khurasan NE, Basra SE, Kufa SW, Syria NW); palace at the centre
Defend the circle in depth: a moat, an outer wall, an open space between the walls, and a massive main wall with towers; bring each road in through a gate that turns, and set a domed chamber over the main gate from which the country can be watched.
Cite this page Chris Paton, “The centre kept empty for palace and mosque”, The Textbook of Architecture, https://textbookofarchitecture.com/rule/baghdad-central-precinct. Text, drawings and models licensed under CC BY-NC 4.0.