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
Where to found a city
Found a city where it can be defended (on a steep height or inside the bend of a river) and where it has healthy air, fresh water close at hand, pasture, farmland and wood; a city that lacks these will not last.
Ibn Khaldun, who served the Nasrid sultan in Granada in 1363–65, treats the choice of site as the founder’s first duty. Protection comes first: a city should stand where attackers find it hard to approach, and a ruler’s citadel on the most defensible point within it. Then comes health (air that does not stagnate, water that is sweet and near) and the means of life: fields, pasture and forest within reach.
Granada fits his description closely. The Alhambra stands on a ridge between the gorges of the Darro and the Genil, fed by a canal brought from the Darro upstream; the city fills the valley and the facing hill of the Albaicín; the irrigated plain of the Vega spreads below.
Related rules
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.
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
Keep trade out of the ruler’s city: move the markets to a suburb outside the walls and give each trade its own street or row, with the noisome trades at the far end.
Where people disagree about the width of a public road, make it seven cubits, and let no one build out into it; lanes that serve only the houses on them may be narrower.
public road ≥ 7 cubits (≈ 3.5 m)
Cite this page Chris Paton, “Where to found a city”, The Textbook of Architecture, https://textbookofarchitecture.com/rule/ibn-khaldun-city-site. Text, drawings and models licensed under CC BY-NC 4.0.