Da Vinci's Ghost (5 page)

Observing from the sidelines as Augustus began to create his empire, Vitruvius must have sensed a once-in-a-lifetime opportunity. He could fill this void. If at the outset of the greatest building campaign the world had ever known no comprehensive guide to architecture existed—well, then, why shouldn’t
he
be the one to write it? How better to help set the empire in order, curry favor with the world’s most powerful ruler, and make a lasting name for himself? Why not, as he would soon put it,
“bring the whole body
of this great discipline to complete order”?

Even during his active career, Vitruvius seems to have stolen time from his official duties to study architectural theory. He found it a fascinating but frustrating pursuit. Over the years—especially late in his career, after Augustus, for reasons unknown, granted him a stipend that allowed him some leisure in his retirement—he managed to locate a number of specialized treatises, primarily by Greek authors: commentaries on individual buildings, discussions of specific technical problems, guides to systems of proportions. But they were
“incomplete drafts
,” he complained, “scattered like fragments.” He felt he could do better—and so he set to work. By the mid-20s
B.C
. he had produced
De architectura libri decem
, or
Ten Books on Architecture
—which, naturally, he dedicated to Augustus.

The
Ten Books
is a curious hybrid. At one level, it’s a rich repository of technical information for practitioners, divided, as its title suggests, into ten discrete books, each of which addresses a different subject. Vitruvius provides advice on just about everything he can think of: how to determine sites for new buildings and new cities; what kind of sand to use in mixing concrete; where to find different kinds of timber; how to construct arches, retaining walls, courtyards, villas, bathhouses, theaters, and temples; what to consider when installing floors and ceilings; ways to find water and build aqueducts; and how to make different kinds of machines—odometers, cranes, hoists, water pumps, catapults, siege engines, and more. The book is much studied in architecture programs today because it was also the first to codify the famous architectural orders used by the Greeks: Doric, Ionic, and Corinthian.

But all of this practical information had limited uses. A true architect can’t just be a master of his trade, Vitruvius insisted. He had to be the kind of well-rounded person who, centuries later, would come to be known as a Renaissance man.
“He ought to be both naturally gifted and amenable
to instruction,” he wrote, and then continued, “Let him be educated, skillful with the pencil, instructed in geometry, know much history, have followed the philosophers with attention, understand music, have some knowledge of medicine, know the opinions of the jurists, and be acquainted with astronomy and the theory of the heavens.”

Why such a broad definition of the architect—and, by extension, architecture? Because, according to Vitruvius, architecture is
the
defining human art. It creates civilization. It constructs homes and lays out cities, bringing people together. It designs
temples, revealing the will of the gods and aligning the man-made with the divine. It produces machines, guaranteeing victory in times of war, and prosperity in times of peace. In sum—as Vitruvius described it and as Augustus was practicing it—it builds empire.

M
UCH OF WHAT
Vitruvius has to say in the
Ten Books
involves some very basic principles. Again and again, whether the matter at hand is the assembly of a retaining wall or the layout of a city, everything comes down to the manipulation of squares and circles—or, as Vitruvius put it,
“the use of the rule
and compasses.” But in writing about circles and squares he was writing about more than just geometry, as his readers knew full well.

Philosophers, mathematicians, and mystics in the ancient world held the view that the circle possessed special symbolic powers. It represented unity and wholeness, the cosmic and the godly. Plato, for example, in one of his most influential and widely read works, the
Timaeus
, had likened the cosmos to a single world body animated by a world soul, the entirety of which was contained within a sphere, which he described as
“a figure the most perfect
and uniform of all.” This idea appealed to many Romans in the age of Julius Caesar and Augustus, especially as they developed their twin obsessions with order and empire.
“I can see nothing more beautiful
,” Cicero wrote not long before Vitruvius produced the
Ten Books
, “than that figure which contains all others, and which has nothing rough in it, nothing offensive, nothing cut into angles, nothing broken, nothing swelling, and nothing hollow.” Only circles and spheres “
have the property of absolute
uniformity in all their parts, of having every extremity equidistant from the center,” he continued; “there can be nothing more tightly bound together.”

Cicero had not just Plato but Aristotle in mind. Aristotle had described the cosmos as a concentric set of spheres, each of which spun at a different rate around a central axis. The word
cosmos
, meaning “order” in Greek, implied all of this—as does the word
universe
, with its suggestion of a giant single turning entity. The earth was the midpoint of the whole system. It didn’t move, but around it rotated the spheres of the moon, the sun, the planets, and finally the stars, together creating the apparent motions of the heavens.

Vitruvius devoted considerable time to describing this system in the
Ten Books
. “The cosmos,” he wrote, “is the all-encompassing system of everything in nature, and also the firmament, which is formed of the constellations and the courses of the stars. This revolves ceaselessly around the earth and sea.” The shape of the cosmos would seem to have little to do with the practice of architecture, but in fact, according to Vitruvius, it had
everything
to do with it—in the design of the cosmos, as he put it,
“the power of nature
has acted as architect.” And what the power of nature, or God, had done for the cosmos, he suggested, the human architect should for his creations—which is why some of the earliest surviving illustrations of the geocentric cosmos appear not in works of ancient astronomy or philosophy, as one might expect, but in the practical treatises of the very kinds of people Vitruvius worked closely with as an architect: Roman land surveyors (
Figure 8
).

God as the architect of the world:
this was an idea that would echo down through the ages. Cicero himself had made a similar
point not long before. The geometrical perfection of the cosmos suggested to many the presence of
“not only an inhabitant
of this celestial and divine abode,” he wrote, “but also a ruler and governor—the architect, as it were, of this mighty and monumental structure.”

The analogy made perfect sense to Vitruvius, who, after all, had dedicated his book to Rome’s divine ruler and governor, Augustus. The job of the architect, he proposed, was to survey the cosmic order of things, grasp its circular animating principles, and then bring them down to Earth. And the way to do
that
, he went on, was with the help of the set square.

In human affairs as in architecture, Romans in the Augustan era fixated on the idea of the square as a complement to the idea of the circle. A good citizen had to be not only well-rounded in the liberal arts but also a model of physical and moral
rectitude:
“foursquare in hands and feet
and mind, and fashioned without a flaw,” as one Greek writer had put it. Rome itself had supposedly been plowed in a circle at its founding, hence the relationship that Varro, for one, suggested between
the words
urbs
(city) and
orbis
(circle)
—but in founding the city, the story went,
Romulus had divided
the circular city into quarters for the purposes of augury, setting in order what future Romans would proudly call
Roma quadrata
(squared Rome).

Figure 8.
One of the earliest surviving depictions of the spherical cosmos, set square against the horizon with the earth (
terra
) at its center. From a sixth-century copy of a Roman land-surveying treatise.

So how would Romulus, in the mythical role of augur-surveyor, have squared his city? Imagine him on a hilltop late one evening, gazing out at the circular horizon. Looking up at the sky, he would have easily located the north celestial pole—
“the pivot of the universe
,” as one Roman surveyor would later describe it. This would have allowed him to divide the sky into quadrants based on the four cardinal directions. A sense of how he might have worked survives in a description by the Roman historian Livy, who wrote in the age of Augustus.
“The augur, with his head veiled
,” Livy recorded, “holding in his hand a crooked and knotless staff called
lituus
… prayed to the gods and fixed the regions from east to west, saying that the southern parts were to the right, and the northern to the left.” The Romans called each quadrant a
templum:
a sacred space carved out of the sky, subject to the act of
contemplatio
. These four parts they would often then divide into twelve smaller sections, each associated with a god who corresponded to the celestial bodies contained in that part of the sky, as in the
templum
of Mars—which, by extension, led to the idea of a temple as we now understand it, and the original sense of religious
contemplation
.

Finding the four cardinal points in the heavens was a critical task.
“These points are charged
with exceptional powers,” the Roman astronomer Marcus Manilius would explain during the reign of Augustus, “because the celestial circle is totally held in position by them, as by external supports. … If they did not clamp it with fetters at the two sides, and at the lowest and highest extremities of its compass, the heaven would fly apart.”

As it was above, so it had to be below. For a city to endure, as one Roman surveyor would write, it had to have
“its origin in the heavens
.” It had to be set square with the cardinal directions, just like the cosmos itself. So after dividing up the night sky an augur would have drawn a circle representing the horizon on the ground with his crooked staff and then traced two lines perpendicularly across it: one extending from north to south, the other from east to west. This plan he might later have confirmed with the help of a sundial, which would have allowed him, by revealing the specific path of the sun over the site, to draw with precision the two principal axes that would determine the layout of the rest of his city: the
decumanus maximus
, which ran from east to west, and the
cardo maximus
, which ran from north to south. The Romans also used the word
cardo
—meaning an axis or pole around which something turns—to describe what the earth and universe themselves revolved around, and it’s a term we still allude to today whenever we refer to the
cardinal
directions.

All of this highlights an important idea. Properly laid out, in the fashion illustrated by land surveyors in their treatises (
Figures 9
and
10
), Roman towns provided citizens with the comforting sense that their lives were in proper alignment with
the divine order. Making their way along the
cardo
, they followed the axis around which all of the cosmic spheres turned; making their way along the
decumanus
, they followed the sun’s course.