Rules · Plans · Geometry · Ornament
Lay the ideal garden out on a circular plan in concentric rings, woods outside, then meadows and orchards, then gardens of knots and clipped evergreens divided by walks, with water and the fountain of the goddess at the centre.
At the end of the first book of the Hypnerotomachia (1499) Poliphilo and Polia sail to the island of Venus. Its garden is described ring by ring with its measurements, its hedges, knots of herbs, topiary figures in box and myrtle, pergolas and pools, and at the centre an amphitheatre round the fountain of Venus. The woodcuts show knot patterns and topiary in the shapes of vases, columns and figures.
The garden is imaginary, but the book’s plates were a source for real ones. The geometrical compartments, the clipped figures and the water at the centre of a plan are those of the Italian garden of the sixteenth century, and the knots appear in the Tudor gardens of England.
To find how thick the pier of an arch must be, divide the intrados into three equal parts; draw a line from the springing through the first division, and produce it beyond the springing by its own length. A vertical through the end of that line marks the outer face of the pier.
pier ≈ ¼ span (semicircle) · ≈ 0.23 span (equilateral) · less for a lancet
To set a round dome on a square bay, imagine a sphere passing through the four corners of the square; cut it by the four vertical planes of the sides and by the horizontal plane of their crowns. The four spherical triangles left in the corners are the pendentives; the circle at their top carries the dome.
sphere radius R = S⁄√2; arches = sphere ∩ side planes (radius S⁄2); ring at h₀ + S⁄2 with radius S⁄2
If the sphere that forms the pendentives is simply continued above the ring, the bay is covered by a single shallow dome, the sail vault or pendentive dome, which springs directly from the four corners.
crown = h₀ + S⁄√2 (lower than a hemisphere on the ring, h₀ + S)
Edge the beds before the portico with box, clip box into figures of animals set facing one another, and in the garden beyond cut it into many shapes, even into the letters of the owner’s name.
Give the villa garden porticoes for sun and for shade, grottoes made in imitation of nature with tufa and shells, evergreens planted in straight rows at equal distances, and hedges of box; set vines on columns over the walks.
On a hillside, cut the garden into level terraces held by retaining walls, join them by stairs and ramps on a single axis that runs from the house, and lead water down the axis from level to level.
Cite this page Chris Paton, “The garden island of Cythera”, The Textbook of Architecture, https://textbookofarchitecture.com/rule/hypnerotomachia-cythera. Text, drawings and models licensed under CC BY-NC 4.0.