Thirty-two engraved plates and almost no text: the most successful architecture book ever printed. Vignola reduced the orders to a single module and a handful of simple ratios that any draughtsman could remember.
Vignola, architect of the Villa Farnese at Caprarola and of the Gesù in Rome, measured the Roman remains and extracted from them a system rather than a set of examples. His rule is almost arithmetic: take the height available, divide it into 19 parts if there is a pedestal (15 without); give 4 parts to the pedestal, 12 to the column and 3 to the entablature; that is, the pedestal is one third and the entablature one quarter of the column.
The column height is then expressed in modules (the lower radius): 14 for Tuscan, 16 for Doric, 18 for Ionic, 20 for Corinthian and Composite. Every other dimension follows. The book was reprinted in hundreds of editions, and until the twentieth century it was the first book most architecture students were given.
The book, part by part
I The rule
The general rule of pedestal, column and entablature in the ratio 4 : 12 : 3, with the column heights of the five orders in modules.
Rules: Vignola’s general rule: 4 : 12 : 3 · Column heights in modules · Vignola’s entasis: straight for a third, curved above
II The orders one by one
For each order: a colonnade, an arcade without and with pedestals, the pedestal, base, capital and entablature drawn large, with every member dimensioned in parts of the module.
III Supplements
The method of drawing entasis, the Ionic volute, and doors, added to later editions.