The Sacred Cut

    Begin with a square. Taking a compass, place the point on the center, and open it to an amount equal to the half a diagonal of the square. Move the point to one corner, and sweep out an arc that cuts a side. That cut divides the side of the square into a long piece and a short piece, and is called the sacred cut.

    The name Sacred Cut may sound like an old name, but it was actually coined in the 1960s by Danish engineer Tons Brunes, in his book The Secrets of Ancient Geometry and its Use. According to Brunes, ancient builders believed that this method gave a way to "square the circle" -- that is, to construct a square with the same perimeter as a given circle, or vice versa.

    To ancient geometers, the circle symbolized the unknowable, spiritual part of the universe and the square represented the comprehendible world.

    Squaring the circle was a means of expressing the unknowable through the knowable, the sacred through the familiar. Hence the term sacred cut.

    (It has been proven for centuries that it is impossible to square the circle geometrically, and yet some people continue to search for ways to do it, as they continue to look for ways to unite the spiritual with the earthly.)

    A System of Proportions Based on the Sacred Cut
    If an ancient architect had a square house or room, and wanted to design an new square room or region that was either half or double the area of the original, he could easily use the idea of sacred cut to create such a new square without measuring. We'll begin with how to create a square with half the area, as we're already nearly there. After creating the sacred cut as above, proceed as follows:
    • Keeping the compass on the same corner, sweep out an arc that cuts the other side into a sacred cut also.
    • Repeat this for the other three corners of the square. Each side will now be cut twice. Disregarding the arcs, and looking only at the cuts, we now have,

    • Through these 8 cuts, draw two vertical lines and two horizontal lines. This will form 4 corner squares, one larger center square, and 4 side rectangles.

    As you can see, this creates several smaller squares, so architects could use this one construction to create a variety of smaller squares inside the original larger one. The center square is called the sacred cut square.

    To see an example of (alleged) extensive use of the Sacred Cut in Ostia, let's look again at The Garden Houses at Ostia

    Back to Systems of Proportion | Back to Inclass homepage