Roman Mosaics; Or, Studies in Rome and Its Neighbourhood

by Hugh Macmillan

Marble fragments are so eagerly sought after because they make most suitable and convenient souvenirs. Their own beauty and rarity, apart from all historical associations, are a great attraction. Many of them will form, when cut and polished by the lapidary, pretty tazzas and paper-weights, and even the smallest bits can be put together in a mosaic pattern, so as to make extremely beautiful table-tops. Whole rows of lapidary shops in the English quarter of the city, especially in the Via Babuino and the Via Sistina, are maintained by this curious traffic. In the Forum and Colosseum great quantities of marble and alabaster used to be found; but these localities have been so much ransacked that they now afford very scanty gleanings. The Baths of Caracalla and Titus, the recent excavations on the Esquiline, the ruins of the palaces of the Cæsars on the Palatine, and the open space marked out for new squares and streets between Sta. Maria Maggiore and St. John Lateran, are the best situations within the walls of the city. Outside the supply is almost as large as ever. All over the vast Campagna the foot of the wayfarer strikes against some precious or beautiful relic; and along the Appian and Latin Ways broken pieces of different kinds may be found in such profusion that such spots look like the rubbish-heap around a marble quarry. In the vast grounds over which the imposing ruins of Hadrian's Villa spread, heaps of fragments of marble flooring or casing may be seen in almost every neglected corner, from which it is easy to obtain some lovely bit of giallo antico or pavonazzetto or green porphyry. Beside the ancient quay of Rome, leading to the ruins of the Emporium or Custom-house—at a spot called in modern phrase "La Marmorata," because marble vessels still discharge their cargoes there—immense quantities of marble, alabaster, and porphyry are piled up, that were unshipped untold ages ago for Roman use; and a vineyard a short way off, on the slope of the Aventine, is much frequented by collectors on account of the richness of its finds.

But it is not as a mere amusement, or as a means of collecting pretty souvenirs of travel, that such marble-hunting expeditions are to be recommended. They may have a much higher value. The different kinds of marble collected are peculiarly interesting owing to their association with the different epochs of the history of the city and empire; and as the specimens which the geologist obtains throw light upon the formation of the rocky strata of the earth, so the small marble fragments which the student finds in Rome afford a clue to the various stages of its existence. Indeed, a competent knowledge of the marbles of Rome is indispensable to a clear understanding of the age of its ancient monuments. An immense amount of controversy has raged round some remarkable building or statue, which would have been prevented had the nature and origin of the marble of which it was composed been first investigated. The famous statue of the Apollo Belvedere in the Vatican, for instance, was long regarded as an original production either of Pheidias himself or of his school. But the discovery that the marble of which it is wrought is Lunar or Carrara marble—which was unknown until the time of Julius Cæsar, who first introduced it into Rome—is of itself a proof that it is not a genuine work of Greek art of the best period, but a monument of the decadence, or a copy of an original, wrought in imperial times for the adornment of a summer palace in Italy. In numberless other cases, ancient monuments have been identified by the mineral character and history of their marble materials. The first thing, therefore, which the student during his visit to the city ought to do, is to make himself acquainted with the different varieties of marble that have been found within the walls or in the neighbourhood. For this purpose the Museum in the Collegio della Sapienza or University of Rome will afford invaluable aid. In this institution, conveniently arranged in glass cases, are no less than 607 specimens of various marbles and alabasters used by the ancient Romans in the building or decoration of their houses and public monuments. The collection was made by the late Signor Sanginetti, Professor of Mineralogy in the University, and is quite unique. A great deal of instruction may also be obtained from the mineralogical study of the thousands of marble columns still standing in the older churches and palaces of Rome, most of which have been derived from the ruins of ancient temples and basilicas. Several excellent books may also be consulted with advantage—especially Faustino Corsi's Treatise on the Stones of Antiquity, Trattato delle Pietre Antiche, which is the most approved Italian work on the subject, and from which much of the information contained in the following pages has been obtained.

No marble quarries exist in the vicinity of Rome. The Sabine Hills are indeed of limestone formation, and large masses of travertine, a fresh-water limestone of igneous origin, occur here and there, but no mineral approaching marble in texture and appearance is found within a very considerable radius of the city. The nearest source of supply is at Cesi, near the celebrated "Falls of Terni," about forty-five miles from Rome, where "Cotanella," the red marble of the Roman States, is found, of which the great columns supporting the arches of the side aisles of St. Peter's are formed. The hills and rocks of Rome are all volcanic, and only the different varieties of eruptive rock were first employed for building purposes. The oldest monuments of the kingly period, such as the Cloaca Maxima, the Mamertine Prison, the Walls of Servius Tullius, and some of the earliest substructures on the Palatine Hill, were all built of the brown volcanic tufa found on or near their sites. This is the material of which the famous Tarpeian Rock and the lower part of most of the Seven Hills is composed. It is the oldest of the igneous deposits of Rome, and seems to have been formed by a conglomerate of ashes and fragments of pumice ejected from submarine volcanoes whose craters have been completely obliterated. It reposes upon marine tertiary deposits, and over it, near the Church of Sta. Agnese, where it is still quarried for building stone, rests a quaternary deposit, in which numerous remains of primeval elephants have been found. Though the Consular or Republican period was a very stormy one, and the reconstruction of the city, after its partial demolition by the Gauls, seems to have been too hurried to allow much attention to be paid to the materials and designs of architecture, yet there are numerous indications in the existing remains of that period that there was a decided advance in these respects upon the ruder art of a former age. Finer and more ornamental varieties of volcanic stone were introduced from a distance, such as the peperino or grayish-green tufa of the Alban Hills, the Lapis Albanus of the ancients, with its glittering particles of mica interspersed throughout its mass; the hard basaltine lava from a quarry near the tomb of Cæcilia Metella, on the Appian Way, and from the bed of the Lago della Colonna, once the celebrated Lake Regillus, to which the name of Lapis Tusculanus or Selce was given; and the Lapis Gabinus or Sperone, a compact volcanic concrete found in the neighbourhood of the ancient Gabii on the road to Tivoli, extensively used in the construction of the earliest monuments, particularly the Tabularium and the huge Arco de Pantani. Brick was also largely employed in the construction of the foundations and inner walls of public buildings, being arranged at a later date into ornamental patterns, to which the names of opus incertum and opus reticulatum were given; and in the manufacture of this substance, which they were probably at first taught by the Etruscan artificers of Veii in the neighbourhood, the Romans reached a high degree of perfection. The earliest tombs along the Appian Way were constructed of these different varieties of building materials. The sarcophagi of the Scipios were hollowed out of simple blocks of peperino stone; and the sculptor's art and the material in which he wrought were worthy of the severe simplicity of the heroic age.

But towards the close of the Republican period, Rome began to be distinguished for the magnificence of its public monuments. As its area of conquest spread, so did its luxury increase. New divinities were introduced from foreign countries, and domesticated in the Capitol; and these required more sumptuous fanes than those with which the native deities had been contented. The brown tufa of the Tarpeian Rock sufficed for the rude sanctuary of Vesta, the primitive hearth-stone of ancient Rome; but in the reconstruction of the sumptuous temple of Jupiter Capitolinus, which marked the grandest period of Roman history, the most precious stones of Asia and Africa were employed. Statues were imported wholesale from Greece to adorn temples and theatres, constructed after the models of Greek architecture, with pillars, friezes, and floors of precious Pentelic and Sicilian marble. During the last century of the Republic marble became a common building-stone. The tomb of Cæcilia Metella, and the temples of Ceres, Juno Sospita, and Castor and Pollux, indicate the introduction of this precious and beautiful material. But it was reserved for the period of the Empire to complete the architectural glories of the city. Travertine, usually called Lapis Tiburtinus, a straw-coloured volcanic limestone excavated in the plain below Tivoli, which has the useful property of hardening on exposure, was now used as the principal building-stone instead of the former lavas and tufas; and the Colosseum, entirely constructed of travertine, which was treated in the middle ages as a quarry, out of which were built many of the palaces and churches of Rome, attests to this day the beauty and durability of this material. Quarries of crystalline marbles, admirably adapted for the purposes of the sculptor and architect, were opened in the range of the Apennines overlooking the beautiful Bay of Spezia, in the vicinity of Carrara, Massa, and Seravezza, and largely worked in the time of Augustus. This emperor could boast that he had found Rome of brick, and left it of marble. The marbles of each new territory annexed to the Empire were brought at enormous expense into the Imperial City. A quay, to which reference has already been made, was constructed at the broadest part of the Tiber, where the vessels that transported marbles from Africa, and from the most distant parts of Eastern Europe and Western Asia, landed their cargoes. Here numerous blocks of marble were lately found, one of which was identified as that sent to Nero from a quarry in Carinthia; and another, a column of even more colossal dimensions, weighing about thirty-four tons of valuable African marble, was meant to serve as a memorial pillar of the Council of 1870 on the Janiculum, but the intention was never carried out. So abundant was marble during the first two centuries of the Empire, that it was nothing accounted of. Every temple, palace, and public edifice was built of it either in whole or in part. The tombs that lined the Appian Way on either side for fifteen miles had their brick cores covered with marble slabs; and their magnificence must have impressed every visitor who entered the Imperial City through this avenue of architectural glory shrouding the decays of death. It is obvious, then, that by studying the history of the conquests of Rome, the student can ascertain at what period a particular kind of marble was introduced from its native country, and the proximate date of the building in which this marble had been used.

It was a fortunate circumstance for the preservation of the precious marbles of Rome that Christianity laid its cuckoo egg in the nest of the Pagan city. When the capture of Rome by Alaric gave the final blow to heathen worship, by the overthrow of the ruling classes, who alone cherished the proud memories of the ancient faith, the greater number of the temples were still standing without any one to look after the edifices or maintain the religious services. The Christians were therefore free to take possession of the deserted shrines; and they speedily transferred to their own churches the columns and marble decorations that adorned the temples of the gods. Many of the precious stones that once beautified the palaces of emperors and senators were employed to form the altars and the mosaic flooring of the memorial chapels. Almost all the early churches were constructed on or near the sites of the temples, so that the materials of the one might be transported to the other with the least difficulty and expense, just as the settler in the back-woods of America erects his log-house in the immediate vicinity of the trees that are most suitable for his purpose. And the striking contrast between the plain, mean exteriors of the oldest Roman churches—rough, time-stained, and unfinished since their erection—and their gorgeous interiors, with their forests of columns separating the aisles, and the series of richly-sculptured and brilliantly-frescoed chapels, all blazing with gold and marble,—a contrast that reminds us of the surprising difference between the outside of a common clumsy geode lying in the mud, and the sparkling crystals in the drusic cavity at the heart of it,—would lead us to infer that the outer walls were raised in haste to secure the valuable materials on the spot, before they could be otherwise appropriated. Marangoni, a learned Roman archæologist, mentions thirty-five churches in Rome as all raised upon the sites and out of the remains of ancient temples; and no less than six hundred and eighty-eight large columns of marble, granite, porphyry, and other valuable stones, as among the relics of heathen fanes transferred to sacred ground within the city, when the bronze Jupiter was metamorphosed into the Jew Peter,

"And Pan to Moses lent his pagan horn."

Many of these relics can be traced and identified, for it may be generally presumed, for the reason already given, that none are very far removed from their original situation.

I know no more interesting pursuit in Rome than such an investigation; the objects, when their history is ascertained, acquiring a charm from association, over and above their own intrinsic beauty and interest. Most of the materials with which the three hundred and sixty-five churches of modern Rome have been constructed have been derived from the ruins of the ancient city. With the exception of a few comparatively insignificant portions brought from the modern quarries of Carrara, Siena, and Sicily, to complete subordinate details and to give a finish to the work, no marbles, it is said, have been used in ecclesiastical and palatial architecture for the last fifteen hundred years, save those found conveniently on the spot; and hardly a brick has been made or a stone of travertine or tufa hewn out for domestic buildings within the same period. The construction of St. Peter's itself involved more destruction of classical monuments than all the appropriations of previous and subsequent Vandals put together. Much has been lost on account of this extraordinary transmutation and reconsecration, whose loss we can never cease to deplore; but we must not forget at the same time that much has been conserved which would otherwise have wasted away under the slow ravages of time, been consigned to the lime-kiln, or disappeared in obscure and ignoble use. Enough remains to overwhelm us with astonishment, and furnish materials for the study of years.

The white marbles of Greece were the first introduced into Rome. Paros supplied the earliest specimens, and long held a monopoly of the trade. Marmor Parium, or Marmo Greco duro, as it is called by the modern Italians, is the very flower and consummation of the rocks. This material seems to have been created specially for the use of the sculptor—as that in which he can express most clearly and beautifully his ideal conceptions; and the surpassing excellence of ancient Greek sculpture was largely due to the suitability for high art of the marble of the country, which was so stainlessly pure, delicate, and uniform—as Ruskin remarks, so soft as to allow the sculptor to work it without force, and trace on it his finest lines, and yet so hard as never to betray the touch or moulder away beneath the chisel. Parian marble is by far the most beautiful of the Greek marbles. It is a nearly pure carbonate of lime of creamy whiteness, with a finely crystalline granular structure, and is nearly translucent. It may be readily distinguished from all other white marbles by the peculiarly sparkling light that shines from its crystalline facets on being freshly broken; and this peculiarity enables the expert at once to determine the origin of any fragment of Greek or Roman statuary. The ancient quarries in the island of Paros are still wrought, though very little marble from this source is exported to other countries. In the entablature around the tomb of Cæcilia Metella, which is composed of Parian marble, we see the first example in Rome of the use of ornaments in marble upon the outside of a building; an example that was afterwards extensively followed, for all the tombs of a later age on the Appian Way had their exteriors sheathed with a veneer of marble. The beautiful sarcophagus which contained the remains of the noble lady for whom this gigantic pile was erected, and which is now in the Farnese Palace, was also formed of this material. Most beautiful examples of Parian marble may be seen in the three elegant columns of the Temple of Castor and Pollux in the Roman Forum, belonging to the best period of Græco-Roman architecture; and in the nineteen fluted Corinthian pillars which form the little circular temple of Hercules on the banks of the Tiber, long supposed to be the Temple of Vesta. By far the largest mass of this marble in Rome is the colossal fragment in front of the Colosseum that belonged to the Temple of Venus and Rome; and it helps to give one an idea of the extraordinary grandeur and magnificence of this building in its prime, whose fluted columns, six feet in diameter, and the sheathing of whose outside walls of great thickness, were all made of Parian marble.