Rules · Cities · Plans · Light
Leave at least twelve feet between a new house and its neighbour; build no balcony lower than fifteen feet from the ground or nearer than ten feet to the house opposite; do not block a neighbour’s view of the sea within a hundred feet; and keep the shops between the columns of the great porticoes small and faced with marble.
gap ≥ 12 ft (≈ 3.7 m) · balcony ≥ 15 ft up, ≥ 10 ft apart · sea view protected within 100 ft
Zeno’s constitution, issued in the late fifth century after disputes and fires in the crowded capital, is the first detailed building code of a medieval city. Its distances protect light, air and escape from fire; its rule on sea views protects property values in a city built on hills above the water; its regulation of the shops in the colonnades of the Mese, from the Milion onward, protects the dignity of the main street.
Justinian extended the law to other cities, and it passed into the later Byzantine law books, the Hexabiblos of Harmenopoulos among them, and through them into the customs of the Orthodox world. It governed not a plan but a pattern: a city of courtyard houses standing a little apart, with projecting upper rooms over the lanes.
Lift the dome on a cylindrical or polygonal drum pierced with windows between the ring of the pendentives and the springing of the dome, to light the centre of the church and to make the dome visible from afar.
drum height ≈ ⅓–1 × its radius (Byzantine); much taller in Russian churches
Pierce the base of the dome with a close ring of windows between buttressing ribs, so that the shell seems to float on light rather than to rest on the arches.
Hagia Sophia: 40 windows and 40 ribs; dome ≈ 31 m across, crown 55.6 m above the floor
To turn a domed square into a long church, open two of its great arches into semidomes of the same radius, and open the semidomes in turn into smaller exedrae, so that the space expands by stages from the central dome.
Hagia Sophia: central square 31 m; two semidomes of radius ≈ 15.5 m; four exedrae; interior ≈ 31 × 70 m
Divide a square naos into nine bays: dome the central one on a drum over four columns, barrel-vault the four arms of the cross, and cover the four corner bays lower; add three apses to the east and a narthex to the west.
arms = central bay width; corners lower; dome on pendentives over four columns
Crown the four corner bays of a cross-in-square with smaller domes on drums around the great central dome, making a five-domed quincunx.
Build the house of assembly long, with its head toward the east and rooms for the clergy on either side of the east end; seat the bishop in the middle of the head with his presbyters about him, and the people in order down its length.
Cite this page Chris Paton, “Twelve feet between houses”, The Textbook of Architecture, https://textbookofarchitecture.com/rule/zeno-house-spacing. Text, drawings and models licensed under CC BY-NC 4.0.