moving by sea, assembling to hear their orders, building fortifications, raiding an enemy town, and crossing the danube in small boats, the army is shown to be an awesome fighting machine. but there is no glorification of war itself, which is necessarily brutal and remorseless. the victory column and the triumphal arch through which the retuturning army marched, dragging slaves and spoils of war, were forceful forms of propaganda for the righteousness of imperial power, guided by the emperor, the senate, and the people of rome. it was the arch that was the basis of a revolutionary new architecture. the post and lintel system of the ancient world was limited in the space it could span and the weight it could bear. the romans soon recognized the arch's strength and versatility and elaborated it into an art form of grandeur and utility. roman stone arches, like the one supporting this bridge built across the tiber in 62 b.c., were constructed of wedge-shaped blocks. the blocks, wider at the top than at the bottom, are locked into place by a central keystone. the weight of the structure compresses the blocks and is transmitted evenly from one to another, on either side, down into the ground. from therch came a new conception of interior architecture extending the arch form through space in a straight line creates a tunnel, or barrel, vault. curving the arch form through space, roman engineers created an annular, or ring, vault. two identical barrel vaults crossing at right angles form a groin vault. these dramatic intersections would find lasting expression in the great romanesque churches of the middle ages. by rotating the arch arou a fixed center point, they could describe a dome or an apse with a half-domed ceiling. but e arch was only part of the story it was an extraordinary new ilding material which made these fluid designs possible. 20 miles from rome, in the hill town of palestrina, stand the remains of one of the first great roman building projects-- the sanctuary of fortuna, the goddess of fortune. much of it was hidden until a world war ii bombing raid sheared away the later housing, revealing this gigantic conception... a series of seven immense terraces rising 400 feet up from the grotto below, where the fortune-telling lots were cast for pilgrims, all the way up to a colonnaded rotunda on top, where the 17th-century palace of the barberini now stands. and the whole complex was aligned to look out over a breathtaking vista of plain and mountain and with axial symmetry, the sea, framed by the foothills of the apennines. here, roman architects began to play with the new curvilinear forms, such as this graceful hemicycle with its colonnade supporting an annular barrel vault inset with coffers that were once richly decorated. this amazing architecture was made possible by something which to us in the 20th century seems so commonplace it would hardly deserve comment-- concrete. concrete had been used before this time-- a simple mixture of three parts sand, one part lime, broken stone, and water. but among its problems for builders was that it dried very swiftly, so it could only really be usefor layering courses, never for building entire structures. but in the first century b.c., the romans discovered the almost magical properties of a reddish volcanic sand called pozzuolana, which comes from pozzuoli near naples. concrete made with pozzuolana has a very different quality. it's very strong. it can be used in wet conditions. it dries slowly, so entire structures could be built, bonded from top to bottom as one, even including domes. so this simple discovery marks a revolution in roman and in western architecture. it made possible all the greatness which would follow. at the height of its imperial power, rome was a sprawling city, crowded with a million citizens and slaves. to keep them occupied, there were public baths, racecourses like the circus maximus, and the great amphitheater decreed by t emperor vespasian in 75 a.d. with its massive facade of superimposed arches, the colosseum seems to express in stone the grandiose dreams of all empire-builders. but it was a most functional building-- its gates numbered for ticket holders, its concentric vaulted corridors designed to funnel 50,000 spectators to their seats with maximum efficiency. built of stone, brick, and concrete, the colosseum's huge oval interior offered every roman an unobstructed view of the slaughter in the arena below-- arena being the latin word for the sand that covered the wooden floor and absorbed the blood. today the colosseum impresses us more as an amazing feat of architecture than as a work of art, though it strongly influenced the design of both renaissance palaces and modern sports arenas. this thr-dimensional scale model depicts rome in the fourth century, virtually at the end of its spectacular imperial building program. of all the great constructions throughout the empire, one stands above all others ashe crowning achievement of roman architecture-- the pantheon. fittingly, it is a work that expresses not the ugliness of our baser instincts, but our sense of wonder about worlds beyond our own. who built the pantheon and when was long a mystery. the latin dedication tells us it was built by marcus agrippa, augustus' son-in-law and consul. this, it turned out, refers to the first pantheon on this site, a much more conventional temple. the answer lay hidden for centuries in the brick facing of the pantheon's 25-foot-thick concrete rotunda. archaeologists had found that many roman bricks were stamped with the name of the consul in office when they were made. almost all the pantheon's bricks were made around 120 a.d., revealing that its builder was the emperor hadrian, a man of passionately artistic sensibility and a particular love for architecture. the pantheon's rotunda and classical-temple porch have inspired more western architecture than any other building. each massive column is carved from a single block of egyptian granite and topped by the flourishing acanthus leaves of the corinthian order favored by the romans. impressive though it is, it isn't the exterior that gives this building its lofty place in western art, but what lies behind its great bronze doors. with its opening to the sky, this was the world's largest dome for more than 18 centuries-- 5,000 tons of carefully molded concrete, stretching across nearly 150 feet of space. the greeks had created exteriors of exquisite harmony. it was the romans who gave the west the grandly conceived interior. now a church, this is the only major roman building that survives intact. "pantheon" means temple of all the gods. their statues must have been placed in these templelike niches where christian saints now stand, richly decorated with colored marble brought by sea from quarries throughout the empire. professor richard brilliant of columbia university. in the fifth century, when the barbarians took rome, they entered this building to despoil it of its treasures. the splendor of the interior stopped them in their tracks and thus preserved this glorious structure, this magnificent space, until our own time. ace gives content and form to this great building. what we see on the ground level is a great cylinder. this cylinder fuses or merges into the hemispherical dome that lies upon it. that fusion is so complete because the architect has shaped this interior both vertically and horizontally in such a way as to suggest that the building interior contains a perfect form, that perfect form known as the sphere. the paradox encountered in this structure is that space so ordinarily thought of as being defined by architecture instead defines architecture. the true substance of the building is space. you can see, the coffers, meant solely to organize, to structure our visual experience, recede towards the oculus, culminating in that passage-- not an escape, but a kind of communication between the interior space defined by this extraordinary building and the space of the cosmos that lies beyond. that cosmos is perfection, perfection in the form of a sphere, a sphere which has no beginning and no end. pagan temple, christian church, bold and original work of art-- the pantheon remains a symbol of universal significance for all the ages. hadrian's restless intelligence was also at work in the immense and inspired villa complex he built for himself near tivoli. like other emperors, he used the shaping power of concrete and vaulted architecture to enclose space in dramatic ways, to sculpt interiors that expanded rather than limited human activity, with an echo here and there of his enduring masterwork. everywhere in the villa, there were statues, many of them in the greek tradition he so passionately admired. in this, hadrian was typical of well-to-do romans throughout the imperial age. roman sculpture, it's such a rich subject. the romans, their artists, roman patrons delighted in the collection of sculpture in the round-- sculpture which they displayed in their public places, sculpture which they used to decorate the fora, palaces, gardens-- a variety of situations-- sculpture, which i may add, they put into museums because, indeed, the delight in works of art was something that gave enormous pleasure both to the romans and also to their friends. indeed, it has become clear that much of greek art has, in fact, survived not in originals, but in roman copies, much like the copies in this room in the capitoline museum in rome. such a special work is this statue in marble, from hadrian's villa of a tormented centaur. the statue in dark marble comes close to the bronze original of the hellenistic period, and one can see what effort the sculptor's expended in attempting to reproduce as closely as possible the ancient original. hadrian, who we must imagine collected this sculpture and enjoyed it, could appreciate a certain moral content in the work itself. the centaur is tormented by lust. at one time-- now missing, unfortunately-- there was a cupid on his back, cupid thrusting the arrows of sexual passion into the centaur, whose arms are bound behind him. the moral lesson to be derived from such a work, and not just from the enjoyment of it, is to be found in the necessity of imposing reason on passion. the romans themselves live on in their vast legacy of portrait sculpture. we have marcus aurelius as an idealistic young man and as the weary philosopher emperor who was to die on a lonely frontier. we have the portrait of this aristocratic beauty of the flavi period, whosslave girls must have been cstantly sy with the curling iron. and by contrast, the flaccid ir and carewornxpression decius ruled an empire more and more threatened by barbarians at its borders and by civil strife within. looking for scapegoats, he ordered the first systematic persecution of christians. a vision of the christian cross was said to have inspired the military victory of constantine over his rival for the imperial crown inhe year 312. this colossal head is a portrait not of constantine the individual, but of his divinely inspired power. the senate honored him with the last triumphal arch built in rome. nervous about constantine's interest in christianity, the senators decorated it not only with new reliefs, but also with earlier works of trajan, hadrian, and marcus aurelius-- reminders of the glorious and pagan roman tradition. they reveal a remarkable change in roman art. the dynamic compositions and ideally proportioned bodies of the reliefs from hadrian's time-- whose head has been replaced by constantine's-- give way in the new reliefs to rows of puppetlike figures, static and without identity. squeezed together as if for security, they seem to express the anxiety and authoritarianism of a troubled empire. while his arch was still being built, constantine legalized the practice of christianity. its art could now rise from the darkness of the catacombs to celebrate the son of god and his promise of life everlasting. junius bassus, prefect of rome, was baptized on his deathbed and buried in this marble sarcophagus. a masterwork of early christian art, it depicts the expulsion of adam and eve, the entry of jesus into jerusalem, daniel in the lion's den, the arrest of saint paul, and other scenes that have become icons of the faith. the central figure is christ, the giver of law, seated on the throne of heaven, flanked by peter and paul. but elements of the pagan past remain. calais, the roman god of the skies, supports the floor of heaven. christ wears the robe of a greek philosopher... and his beardless, youthful face bears more than a passing resemblance to pagan images of apollo. the first great churches were variations of the roman assembly hall known as a basilica, with a central nave often ending in a semicircular apse and side aisles screened by colonnades. santa sabina, finished in 432, is a particularly fine example of these simple but elegant early christian basilicas. the roman arch appears here in yet another form, springing directly from the column capitals. the insignia of the new christianized empire, whose capital is no longer rome but constantinople, are placed with perhaps unconscious symbolism atop the corinthian columns taken from a pagan building. once reviled and persecuted, christianity is triumphant. historians havargued about the causes of the fall of the roman empire ever since it happened, when saint augustine wrote that the empire had been part of god's divine plan for the furtherance of christianity through the world, that it had now fulfilled its historical purpose. modern scholars have found political, material, economic, social reasons for the decline, but have been most impressed by the spiritual crisis which swept through all roman classes in the fourth century and is marked by the breakdown of the social, ethical, and religious concepts which had bound the classical world view together. the roman empire had brought to its rulers inconceivable wealth, as we can still see today in its vast building projects. but the rights of individual people to moral fulfillment had never been met. so the rise of christianity, the superseding of the great pagan temples of rome-- like this one of antoninus pius-- by christian churches, marks a fundamental sht in the western story into the inner life, towards personal salvation. the successors of the roman empire would be the barbarians-- angles, saxons, franks, goths-- third world immigrants, attracted to the fading splendors as to a gold rush. they received the latin language and the christian faith from rome and assimilated roman ideas of government to their own customary law. and there lies the key to the synthesis which will become the western tradition, a synthesis of greco-roman, judeo-christian, and germanic. and that synthesis would be achieved during the long struggles of the dark ages which followed on the fall of the roman empire. captioning performed by the national captioning institute, inc. captio copyright 1989 educational broadcastingcoon annenberg media ♪ world is by movado, makers of the modo museum watch, the watch dial design in the permanent collections of museums thughout the world. addition funding for this program made possible by the financial support of...