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How far apart? Vitruvius’s five spacings of columns
The space between two columns is the intercolumniation. Vitruvius measures it as the clear distance between the shafts at their foot, in lower diameters, and names five arrangements in Book III, chapter 3, crediting the rules to the Hellenistic architect Hermogenes. Four have fixed figures; the fifth is defined only as too wide.
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
| Name | Clear space | Column height | Vitruvius’s examples and comments |
|---|---|---|---|
| Pycnostyle, close-set | 1½ D | 10 D | The temple of the Divine Julius; Venus in the forum of Caesar. |
| Systyle | 2 D | 9½ D | Equestrian Fortune near the stone theatre; the space between the plinths equals the width of a plinth. |
| Eustyle, well-spaced | 2¼ D; middle bays 3 D | 9½ D | The best arrangement; the temple of Bacchus at Teos. |
| Diastyle, wide-set | 3 D | 8½ D | Apollo and Diana; the architraves are liable to break. |
| Araeostyle, too wide | more than 3 D | 8 D | Timber architraves only; Ceres by the Circus Maximus, Pompey’s Hercules, the Capitol. |
Too close and too wide
Vitruvius objects to the two close spacings on practical grounds. Women going up the steps to pray cannot pass between the columns arm in arm and must go in single file; the doors are hidden behind the columns, the statues are thrown into shadow and the walk round the temple is cramped (III.3.3). The wide spacings fail the other way. In the diastyle the stone architraves may crack over the long spans; in the araeostyle stone cannot be used at all, and the beams must be of timber, which makes the temples look low, broad and heavy-roofed, with their pediments decorated in the Tuscan manner with statues of terracotta or gilt bronze (III.3.4–5). For the araeostyle he gives no figure and says the columns may be set as far apart as one likes (III.4.3); the model below uses 4 diameters.
The eustyle
The eustyle is the arrangement Vitruvius recommends for convenience, beauty and strength: 2¼ diameters between the columns, widened to 3 in the middle bay of the front and the back, so that the entrance is clear (III.3.6). He gives the method in modules of one diameter. The front is divided into 11½ parts for four columns, 18 for six and 24½ for eight, and the columns are 9½ modules high (III.3.7). The figures check: four columns of one module, two side bays of 2¼ and a middle bay of 3 make 11½; six columns, four side bays and a middle bay make 18.
Wider spacing, stouter columns
The spacing also fixes the slenderness of the column. Vitruvius makes the column 8 diameters high in the araeostyle, 8½ in the diastyle, 9½ in the systyle and the eustyle, and 10 in the pycnostyle (III.3.10). His reason is optical: in a wide bay the surrounding air seems to eat into the shaft, and a column of nine or ten diameters looks thin and mean; in a close colonnade a column of eight diameters looks swollen (III.3.11). The same reasoning makes the corner columns a fiftieth thicker than the rest, since they are seen against open sky.
Make the corner columns thicker than the rest by a fiftieth of their diameter, because, seen against the open sky, they look thinner than they are.
D corner = D × (1 + 1⁄50); Parthenon: 1.95 m against 1.905 m
The Doric exception
In the Doric the frieze decides the spacing. A triglyph stands over every column and over the middle of each bay, and the metopes between are square, so the distance from axis to axis must be a whole number of triglyph-and-metope units of 2½ modules, the module here being half a diameter. Vitruvius gives two cases. With one triglyph over each bay the axes are 5 modules apart and the clear space 3 modules, or 1½ diameters; he calls this systyle, and the front is 19½ modules for four columns, 29½ for six (IV.3.7). With two triglyphs the axes are 7½ modules apart and the clear space 5½ modules, or 2¾ diameters; he calls this diastyle, and the front is 27 modules for four columns and 42 for six, the middle bay taking three triglyphs (IV.3.3–4). The names do not match the Ionic figures: his Doric systyle has the clear space of the Ionic pycnostyle, and his Doric diastyle falls a quarter of a diameter short of the Ionic one.
Set a triglyph over the axis of every column and over the middle of every intercolumniation (or two, in a wider bay); make the metopes between them as wide as they are high.
axis spacing = n × (triglyph + metope) = n × 2½ M
Greek practice
The Greek buildings follow none of the five. At the Parthenon the lower diameter is 1.905 m and the axial spacing 4.296 m, which leaves a clear space of about 2.39 m, or 1¼ diameters: closer than Vitruvius’s pycnostyle. The corner bays are narrower still, contracted to resolve the Doric corner. Vitruvius’s classes describe the Hellenistic and Roman temples he knew, not the classical temples of Athens.
The flanks follow from the front. Vitruvius gives a peripteral temple twice as many intercolumniations along the sides as across the front, so that its length is twice its width (Twice as many intercolumniations on the flanks).
Cite this page Chris Paton, “How far apart? Vitruvius’s five spacings of columns”, The Textbook of Architecture, https://textbookofarchitecture.com/guide/intercolumniation. Text, drawings and models licensed under CC BY-NC 4.0.