Arches, vaults, and concrete permitted the Romans to create vast
uninterrupted interior spaces for the first time in the history of
architecture. These were explored especially in the great baths, or
thermae, which had become important centers of social life in Imperial
Rome. The experience gained there could then be applied to other, more
traditional types of buildings, sometimes with revolutionary results.
Interior of Pantheon
250. The Interior of the
Pantheon. Painting by GIOVANNI PAOLO PANINI. ñ 1740.
The National Gallery of Art,
Washington, D.C. Samuel H. Kress Collection
251. Plan of the Pantheon
252. Transverse section of the
Perhaps the most striking example of this process is the famous Pantheon
in Rome, a very large round temple of the early second century A.D.
whose interior is the best preserved, as well as the most impressive, of
any surviving Roman structure (figs. 250, 252, 253). There had been
round temples long before this time, but their shape, as represented by
the "Temple of the Sibyl" (see figs. 242 and 243), is so
different from that of the Pantheon that the latter could not possibly
have been derived from them. On the outside, the cella of the Pantheon
appears as an unadorned cylindrical drum, surmounted by a gently curved
dome. The entrance is emphasized by a deep porch of the kind familiar to
us from standard Roman temples (see figs. 240 and 241).
The junction of these two elements seems rather abrupt, but we must
remember that we no longer see the building as it was meant to be seen.
Today the level of the surrounding streets is a good deal higher than it
was in antiquity, so that the steps leading up to the porch are now
submerged. Moreover, the porch was designed to form part of a
rectangular, colonnaded forecourt, which must have had the effect of
detaching it from the rotunda. So far as the cella is concerned,
therefore, the architect apparently discounted the effect of the
exterior, putting all the emphasis on the great domed space that opens
before us with dramatic suddenness as we step through the entrance.
253. The Pantheon, Rome.
That the architects did not have an easy time with the engineering
problems of supporting the huge dome may be deduced from the heavy
plainness of the exterior wall. Nothing on the outside, however, gives
any hint of the interior. Indeed, its airiness and elegance are utterly
different from what the rather forbidding exterior would lead us to
expect. The impact of the interior, awe-inspiring and harmonious at the
same time, is impossible to convey in photographs. Even the painting (fig.
250) that we use to illustrate it fails to do it justice.
The dome is a true hemisphere. The circular opening in its center
(called the oculus, or eye) admits an ample and wonderfully even flow of
light. The height from the floor to the eye is 143 feet, which is also
the diameter of the dome's base and the interior (fig. 252). Dome
and drum are likewise of equal heights, so that all the proportions are
in exact balance. On the exterior, this balance could not be achieved,
for the outward thrust of the dome had to be contained by making its
base considerably heavier than the top. (The thickness of the dome
increases downward from 6 feet to 20 feet.) The weight of the dome does
not rest uniformly on the drum but is concentrated on the eight wide
"pillars" (see fig. 251). Between them, niches are daringly
hollowed out of the massive concrete, and although they are closed in
back, the screen of columns gives them the effect of openings that lead
to adjoining rooms. This sense of open space behind the supports helps
to prevent us from feeling imprisoned inside the Pantheon and makes us
feel that the walls are less thick and the dome much lighter than is
actually the case. The columns, the colored marble paneling of the wall
surfaces, and the floor remain essentially as they were in Roman times.
Originally, however, the recessed coffers were gilded to make the dome
resemble "the golden Dome of Heaven."
As its name suggests, the Pantheon was dedicated to all the gods or,
more precisely, to the seven planetary gods. (There are seven niches.)
It seems reasonable, therefore, to assume that the golden dome had a
symbolic meaning, that it represented the Dome of Heaven. Yet this
solemn and splendid structure grew from rather humble antecedents. The
Roman architect Vitruvius, writing more than a century earlier,
describes the domed steam chamber of a bathing establishment that
anticipates (undoubtedly on a very much smaller scale) the essential
features of the Pantheon: a hemispherical dome, a proportional
relationship of height and width, and the circular opening in the center
(which could be closed by a bronze shutter on chains to adjust the
temperature of the steam room).
The Basilica of Constantine, from the early fourth century A.D., is a
similar example. Unlike other basilicas, which we will discuss below,
its shape is derived from the main hall of the public baths built by two
earlier emperors, Caracalla and Diocletian, but it is built on an even
grander scale. It must have been the largest roofed interior in all of
Rome. Today only the north aisle, consisting of three huge
barrel-vaulted compartments, is still standing (fig. 254). The
center tract, or nave, covered by three groined vaults (figs. 255
and 256), rose a good deal higher. Since a groined vault
resembles a canopy, with all the weight and thrust concentrated at the
tour corners (sec fig. 239), the upper walls of the nave could be
pierced by large windows (called the clerestory), so that the interior
of the basilica must have had a light and airy quality despite its
enormous size. We meet its echoes in many later buildings, from churches
to railway stations.
The Basilica of Constantine.
Rome, ñ. 310-20 A.D.
255. Reconstruction drawing of the
Basilica of Constantine
256. Plan of the Basilica of
Basilicas, long halls serving a variety of civic purposes, had first
been developed in Hellenistic Greece. Under the Romans, they became a
standard feature of every major town, where one of their chief functions
was to provide a dignified setting for the courts of law that dispensed
justice in the name of the emperor. Rome itself had a number of
basilicas, but very little remains of them today. Those in the provinces
have fared somewhat better. The outstanding one at Leptis Magna in North
Africa (figs. 257 and 258) has most of the characteristics
of the standard type. The long nave terminates in a semicircular niche,
or apse, at either end. Its walls rest on colonnades to provide access
to the side aisles, which are lower than the nave to permit clerestory
windows in the upper part of the nave wall.
These basilicas had wooden ceilings instead of masonry vaults, for
reasons of convenience and tradition rather than technical necessity.
They were thus subject to destruction by fire. The one at Leptis Magna,
sadly mined though it is, counts among the best-preserved examples. The
Basilica of Constantine in Rome was a daring attempt to create a novel,
vaulted type, but the design seems to have met with little public favor,
as it had no direct successors. Perhaps people felt that it lacked
dignity because of its obvious resemblance to the public baths. Whatever
the reason, the Christian basilicas of the fourth century were modeled
on the older, wooden-roofed type (see fig. 302). Not until 700
years later did vaulted basilican churches become common in western
257. Basilica, Leptis Magna, Libya.
Early 3rd century
258. Plan of the Basilica, Leptis
Huge northern aisle of the Basilica of Maxentius in Rome.
The Basilica of Maxentius and Constantine (sometimes known as the
Basilica Nova - meaning "new basilica" - or Basilica of Maxentius) is an
ancient building in the Roman Forum, Rome, Italy. It was the largest
building in the Forum.
Construction began on the northern side of the forum under the emperor
Maxentius in 308, and was completed in 312 by Constantine I after his
defeat of Maxentius at the Battle of the Milvian Bridge.
The building consisted of a central
nave covered by three groin vaults suspended 39 meters above the floor
on four large piers, ending in an apse at the western end containing a
colossal statue of Constantine (remnants of which are now in a courtyard
of the Palazzo dei Conservatori of the Musei Capitolini). The lateral
forces of the groin vaults were held by flanking aisles measuring 23 by
17 metres (75 x 56 feet). The aisles were spanned by three semi-circular
barrel vaults perpendicular to the nave, and narrow arcades ran parallel
to the nave beneath the barrel vaults. The nave itself measured 25
metres by 80 metres (83 x 265 feet) creating a 4000 square meter floor.
Like the great imperial baths, the basilica made use of vast interior
space with its emotional effect.
Running the length of the eastern face of the building was a projecting
arcade. On the south face was a projecting (prostyle) porch with four
columns (tetrastyle). The south and central sections were probably
destroyed by the earthquake of 847. All that remains of the basilica is
the north aisle with its three concrete barrel vaults. The ceilings of
the barrel vaults show advanced weight-saving structural skill with
octagonal ceiling coffers.
In modern usage, a basilica has come to
be defined as a place of worship; during ancient Rome, it was a
combination of a court-house, council chamber and meeting hall. There
were, however, numerous statues of the gods displayed in niches set into
the walls. The wrestling events were held here during the 1960 Summer
The color of the building before it was
destroyed was white. On the outside wall of the basilica, facing onto
the via dei Fori Imperiali, are contemporary maps showing the various
stages of the rise of the Roman Empire which were added during the
Fascist regime of Benito Mussolini. A map depicting Mussolini's "New
Roman Empire" was removed from the wall after the war.
One of the delights in studying Roman architecture is that it includes
not only great public edifices but also a wide variety of residential
dwellings, from Imperial palaces to the quarters of the urban poor. If
we disregard the extremes of this scale, we are left with two basic
types that account for most of the domestic architecture that has
survived. The damns is a single-family house based on ancient Italic
tradition. Its distinguishing feature is the atrium, a square or oblong
central hall lit by an opening in the roof, around which the other rooms
are grouped. In Etruscan times, it had been a rural dwelling, but the
Romans "citified" and elaborated it into the typical home of the
Many examples of the domus in various stages of development have come to
light at Herculaneum and Pompeii, the two towns that were buried under
volcanic ash during an eruption of Mount Vesuvius in 79 A.D. As we enter
the so-called House of the Silver Wedding at Pompeii, we see the view in
figure 259, taken rrom the vestibule, along the main axis of the
domus. Here the atrium has become a room of impressive size. The four
Corinthian columns at the corners of the opening in the roof give it the
quality of an enclosed court. There is a shallow basin in the center to
catch the rainwater (the roof slants inward). The atrium was the
traditional place for keeping portrait images of the ancestors of the
family. At its far end, to the right, we see a recess for keeping family
records (the tablinum) and beyond it the garden, surrounded by a
colonnade (the peristyle). In addition to the chambers grouped around
the atrium, there may be further rooms attached to the back of the
house. The entire establishment is shut off from the street by
windowless walls. Obviously, privacy and self-sufficiency were important
to the wealthy Roman.
259. Atrium, House of the Silver
260. Insula of the House of Diana,
Ostia. ñ. 150 A.D.
Less elegant than the domus, and decidedly urban from the very start, is
the insula, or city block, which we find mainly in Rome itself and in
Ostia, the ancient port of Rome near the mouth of the Tiber. The insula
anticipates many features of the modern apartment house. It is a
good-sized concrete-and-brick building (or a chain of such buildings)
around a small central court, with shops and taverns open to the street
on the ground floor and living quarters for numerous families above.
Some insulae had as many as five stories, with balconies above the
second floor (fig. 260). The daily life of the artisans and
shopkeepers who inhabited such an insula was oriented toward the street,
as it still is to a large extent in modern Italy. The privacy of the
domus was reserved for the minority who could afford it.
Late Roman Architecture
In discussing the new forms based on arched, vaulted, and domed
construction, we have noted the continued allegiance to the Classical
Greek orders. If they no longer relied on them in the structural sense,
Roman architects remained faithful to their spirit by acknowledging the
aesthetic authority of the post-and-lintel system as an organizing and
articulating principle. Column, architrave, and pediment might be merely
superimposed on a vaulted brick-and-concrete core, but their shape, as
well as their relationship to each other, was still determined by the
original grammar of the orders.
261. Market Gate from Miletus
(restored), ñ 160
A.D. Antikensammlung, Staatliche Museen, Berlin
This orthodox, reverential attitude toward the architectural vocabulary
of the Greeks prevailed, generally speaking, from the Roman conquest of
Greece until the end of the first century A.D. After that, we find
increasing evidence of a contrary trend, of a taste for imaginative,
"ungrammatical" transformations of the Greek vocabulary. Just when and
where it began is still a matter of dispute. There is some evidence that
it may go back to late Hellenistic times in the Near East. The tendency
certainly was most pronounced in the Asiatic and African provinces of
the Empire. A characteristic example is the Market Gate from Miletus of
about 160 A.D. (rebuilt in the state museums in Berlin; fig. 261).
One might refer to it as display architecture in terms both of its
effect and of its ancestry, for the picturesque facade, with its
alternating recesses and projections, derives from the architectural
stage backgrounds of the Roman theater. The continuous in-and-out rhythm
has even seized the pediment above the central doorway, breaking it into
Equally astonishing is the small Temple of Venus at Baalbek, probably
built in the early second century A.D. and refurbished in the third (figs.
262 and 263). The convex curve of the cella is effectively
counterbalanced by the concave niches and the scooped-out base and
entablature, introducing a new play of forces into the conventional
ingredients of the round temple (compare figs. 242 and 243).
262. Temple of Venus, Baalbek,
Lebanon. First half of the 3rd
263. Schematic reconstruction of
Temple of Venus, Baalbek
By the late third century, unorthodox
ideas such as these had become so well established that the traditional
grammar of the Greek orders was in process of dissolution everywhere. At
the end of the peristyle in the Palace of Diocletian (fig. 264)
at Spalato (Split), the architrave between the two center columns is
curved to create a novel effect by echoing the arch of the doorway
below. On either side we see an even more revolutionary device: a series
of arches resting directly on columns. A few isolated instances of such
an arcade can be found earlier, but it was only now, on the eve of the
victory of Christianity, that the marriage of arch and column became
fully legitimate. The union, indispensable to the future development of
architecture, seems so natural to us that we can hardly understand why
it was ever opposed.
264. Peristyle, Palace of
Diocletian, Spalato (Split), Croatia, ñ 300