The Sacred Cut in the Garden Houses at Ostia

Donald and Carol Watts, professors of architecture at the University of Kansas, have studied the Garden Houses at Ostia. Some of their conclusions are summarized below, along with some of the drawings from their article "A Roman Apartment Complex", from Scientific American, Volume 255 #6, December 1986, pp 132-139.
The outer perimeter of the complex is irregular -- probably because it was built between pre-existing streets.
Be aware that the photo is not oriented so that the north is on the top! In the photo, the north is on the right, the east is on the bottom, the south is on the left and the west is on the top.

In this picture, north is on the top. To compare this with the above photo, mentally rotate it 90 degrees clockwise.
Despite the uneven-ness of the perimeter, the Watts were able to find a reference square that approximately follows the perimeter of the complex.
They were able to convince themselves that their choice of a square wasn't arbitrary, by observing that if they draw a circle centered at the center of the square, with radius = half the length of the side, that circle touches all four corners of the courtyard!

The sacred cuts of the east and west sides of the square mark how far in the northernmost and southernmost walls of the two courtyard buildings are, as well as giving the locations for four of the six fountains.

The inner edges of the fountains to the east and west, and of the courtyard walls to the north and south, define a second reference square.
Sacred cuts of this square define the spines of the courtyard buildings, along which thick party walls separated back-to-back apartments.

The Watts then looked at the Sacred Cut square of this last square -- the innermost square. When they looked at the sacred cuts on this square, they found they marked the position of the innermost walls of the courtyard buildings, the walls closest to the center of the complex, which bound the central east-west corridor.

The diagonal of the smallest sacred-cut square in the above sequence is equal to the outside width of the courtyard buildings. To illustrate this, you see the the sacred cut square of the last square in between the two courtyard buildings. They have then rotated that square 45 degrees, and placed it in the center of each courtyard building. As you can see, from top to bottom (along the diagonal), the corners of the square line up with the walls of each courtyard building.
Each building is also five of these squares in length. The central square in the row of five encloses the stairways and the entrance halls of the building, whereas the squares on both sides define the living spaces.

The Watts claim the Sacred Cut continues to show up in the individual apartments of the Garden Houses at Ostia as well as in the larger plan for the complex. In their article, "A Roman Apartment Complex", they write:
Here [in the individual apartments], the sacred cut serves not as a method of positioning design elements but as a source of a series of proportional, whole-number dimensions that regulate the plan of the apartments.... 58 Roman feet ... is the inside rather than the outside width of the courtyard buildings. (A Roman foot is .295 meter, or roughly 11 1/2 inches.) ... The interior width of an apartment is 28 feet, or four times seven feet. The width of the medianum (the narrow central room) and of the the bedrooms is half of that, or 14 feet. The windows in the largest room are five feet wide; the space between them is two feet, and so the width of a window unit is seven feet. Hallways inside the apartments are five feet across. The width of the public space, consisting of the covered passageway and the stairways to the upper stories, is 17 feet.
Let's do some calculations to see what these numbers have to do with the Sacred Cut, if anything!
More Ratios Close to the Sacred Cut Ratios

The Watts also write in their article,
At the smallest scale in the Garden Houses the sacred cut underlies the design of individual floor, wall and ceiling decorations. None of the decorations in the courtyard buildings are well preserved, but some have survived in the perimeter. In a building called the House of the Muses, at the northeast corner of the complex, a square floor mosaic fills most of one room. In the center of the mosaic there is a square medallion; its size is defined by the sacred cut of the outer border. Similar compositions are found in other parts of the Garden Houses. In some cases the mosaics in different rooms of the same apartment seem to be related in size and geometry. For example, the mosaic in one room may be the size of the sacred-cut square of the mosaic in a larger room.

The Watts continue:

In addition to having floor mosaics it is likely that most of the rooms in the Garden Houses were decorated with brightly colored ceiling and wall paintings. None of the ceiling paintings are intact, but there are enough fragments of one of them to make it possible to reconstruct its composition. Like the floor mosaics it is square and centralized. Sacred cuts of the outer square determine the positions of two sets of arcs; the sacred-cut square of the outer border is then cut again to define a central medallion.
Paintings on the interior walls also give evidence of the sacred cut. To be sure, many of the walls are not square, being either wider than they are high or higher than they are wide. Nevertheless, in almost all the preserved paintings the composition appears to be based on a conceptual reference square whose sides are the width of the wall. The geometry of the sacred cut not only determines the placement of major elements of the composition but also, as in the apartment plans, provides a set of numbers that govern crucial dimensions in the painting.
The sacred cut['s] ... insistent repetition at all scales in the Garden Houses of Ostia suggests that it had a kind of ritualistic importance.

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	Donald and Carol Watts, professors of architecture at the University of Kansas, have studied the Garden Houses at Ostia. Some of their conclusions are summarized below, along with some of the drawings from their article "A Roman Apartment Complex", from Scientific American, Volume 255 #6, December 1986, pp 132-139. The outer perimeter of the complex is irregular -- probably because it was built between pre-existing streets. Be aware that the photo is not oriented so that the north is on the top! In the photo, the north is on the right, the east is on the bottom, the south is on the left and the west is on the top.
	In this picture, north is on the top. To compare this with the above photo, mentally rotate it 90 degrees clockwise. Despite the uneven-ness of the perimeter, the Watts were able to find a reference square that approximately follows the perimeter of the complex. They were able to convince themselves that their choice of a square wasn't arbitrary, by observing that if they draw a circle centered at the center of the square, with radius = half the length of the side, that circle touches all four corners of the courtyard!
	The sacred cuts of the east and west sides of the square mark how far in the northernmost and southernmost walls of the two courtyard buildings are, as well as giving the locations for four of the six fountains.
	The inner edges of the fountains to the east and west, and of the courtyard walls to the north and south, define a second reference square. Sacred cuts of this square define the spines of the courtyard buildings, along which thick party walls separated back-to-back apartments.
	The Watts then looked at the Sacred Cut square of this last square -- the innermost square. When they looked at the sacred cuts on this square, they found they marked the position of the innermost walls of the courtyard buildings, the walls closest to the center of the complex, which bound the central east-west corridor.
	The diagonal of the smallest sacred-cut square in the above sequence is equal to the outside width of the courtyard buildings. To illustrate this, you see the the sacred cut square of the last square in between the two courtyard buildings. They have then rotated that square 45 degrees, and placed it in the center of each courtyard building. As you can see, from top to bottom (along the diagonal), the corners of the square line up with the walls of each courtyard building. Each building is also five of these squares in length. The central square in the row of five encloses the stairways and the entrance halls of the building, whereas the squares on both sides define the living spaces.
	The Watts claim the Sacred Cut continues to show up in the individual apartments of the Garden Houses at Ostia as well as in the larger plan for the complex. In their article, "A Roman Apartment Complex", they write: Here [in the individual apartments], the sacred cut serves not as a method of positioning design elements but as a source of a series of proportional, whole-number dimensions that regulate the plan of the apartments.... 58 Roman feet ... is the inside rather than the outside width of the courtyard buildings. (A Roman foot is .295 meter, or roughly 11 1/2 inches.) ... The interior width of an apartment is 28 feet, or four times seven feet. The width of the medianum (the narrow central room) and of the the bedrooms is half of that, or 14 feet. The windows in the largest room are five feet wide; the space between them is two feet, and so the width of a window unit is seven feet. Hallways inside the apartments are five feet across. The width of the public space, consisting of the covered passageway and the stairways to the upper stories, is 17 feet. Let's do some calculations to see what these numbers have to do with the Sacred Cut, if anything! More Ratios Close to the Sacred Cut Ratios
	The Watts also write in their article, At the smallest scale in the Garden Houses the sacred cut underlies the design of individual floor, wall and ceiling decorations. None of the decorations in the courtyard buildings are well preserved, but some have survived in the perimeter. In a building called the House of the Muses, at the northeast corner of the complex, a square floor mosaic fills most of one room. In the center of the mosaic there is a square medallion; its size is defined by the sacred cut of the outer border. Similar compositions are found in other parts of the Garden Houses. In some cases the mosaics in different rooms of the same apartment seem to be related in size and geometry. For example, the mosaic in one room may be the size of the sacred-cut square of the mosaic in a larger room.
	The Watts continue: In addition to having floor mosaics it is likely that most of the rooms in the Garden Houses were decorated with brightly colored ceiling and wall paintings. None of the ceiling paintings are intact, but there are enough fragments of one of them to make it possible to reconstruct its composition. Like the floor mosaics it is square and centralized. Sacred cuts of the outer square determine the positions of two sets of arcs; the sacred-cut square of the outer border is then cut again to define a central medallion. Paintings on the interior walls also give evidence of the sacred cut. To be sure, many of the walls are not square, being either wider than they are high or higher than they are wide. Nevertheless, in almost all the preserved paintings the composition appears to be based on a conceptual reference square whose sides are the width of the wall. The geometry of the sacred cut not only determines the placement of major elements of the composition but also, as in the apartment plans, provides a set of numbers that govern crucial dimensions in the painting. The sacred cut['s] ... insistent repetition at all scales in the Garden Houses of Ostia suggests that it had a kind of ritualistic importance.