Plan the principal hall as a long rectangle entered on its short side through a porch with two columns between the side walls and a vestibule, and put a great round hearth in the centre of the hall, ringed by four columns carrying a raised roof.
Rules · Cities · Plans · Spacing
The Greek agora: square, ringed by stoas
Make the Greek agora square, surround it with spacious colonnades, double if possible, with close-set columns and architraves of stone or marble, and walks above on an upper floor.
Vitruvius contrasts the Greek agora with the Roman forum (The forum: two parts broad to three long): no gladiatorial shows are held in it, so it can be square and its colonnades closely spaced. At Priene stoas enclose the agora on three sides; the fourth is the main street, beyond which the long Sacred Stoa of two aisles, given by a king of Cappadocia in the second century BC, closes the view.
Related rules
A Doric frieze cannot obey all three of its rules at a corner: triglyphs over the column axes, a triglyph turning the corner, and metopes as broad as they are high. One of them must give way.
displacement of the corner triglyph = e − t⁄2 (e = half-depth of the architrave, t = triglyph width)
To end the frieze with a triglyph at the corner and keep every metope square, move the corner column inward: make the last intercolumniation narrower than the others by the amount the corner triglyph is displaced.
contraction c = e − t⁄2; Parthenon: 4.29 m normal, 3.68 m at the corners (c ≈ 0.61 m)
Let one simple ratio govern the whole: at the Parthenon the lower diameter is to the axial spacing, the width of the stylobate to its length, and the height of the order to the width of the front, all very nearly as 4 is to 9.
D : axial spacing ≈ 1.905 : 4.296 ≈ 4 : 9; stylobate 30.88 : 69.50 ≈ 4 : 9
Plan a Greek theatre by inscribing three squares in the orchestra circle; the side nearest the scene fixes the front of the stage (proscaenium), and the scene is set back to a line tangent to the circle.
proscaenium at r cos 45° ≈ 0.71 r from the centre; logeion 10–12 ft high
Columns may be spaced 1½ diameters apart (pycnostyle), 2 (systyle), 2¼ (eustyle), 3 (diastyle) or more (araeostyle). The eustyle, with a wider central bay of 3 diameters, is the best for use and beauty.
clear space = 1½ · 2 · 2¼ · 3 · >3 D
Cite this page Chris Paton, “The Greek agora: square, ringed by stoas”, The Textbook of Architecture, https://textbookofarchitecture.com/rule/vitruvius-greek-agora. Text, drawings and models licensed under CC BY-NC 4.0.