The collection of colored marble is the result of a donation made in 2003 by the Augustinian Fathers of the Convent of Holy Trinity of Viterbo at the then Faculty of Conservation of Cultural Heritage. The collection, which originally included about 150 samples of rocks and minerals, also currently kept at the University Museum Network is made up of about 100 specimens and was collected between 1898 and 1919 by the then Prior General of the Augustinian Fathers Tommaso Rodriguez.
The samples of colored marbles, mostly of ancient origin, represent a large part of the colored marbles that, in particular in imperial times, found wide use within the ancient Roman architecture. Many of the specimens of the collection are pertinent to cladding slabs of ancient buildings, probably collected in Rome or in the Roman suburb, while others were probably acquired in marble workshops at the time of the collection formation. Several specimens have been cut to obtain the socalled “marmette” (small marble slabs), according to the nineteenth-century taste, others, however, for reasons unknown to us, show only the preparatory engraving for the cut that has never been made.
The exhibition of the Museum Network consists of a selection of some exemplars of polychrome marble among the most significant and best preserved within the collection, all of ancient origin. A few years ago, the entire collection was the subject of a degree thesis that allowed the study and recognition of the set of different marble lithotypes present in it.
Marble in ancient Rome
The term marble generally refers to all rocks, polychrome or not, likely to acquire shine after being subjected to polishing. The etymon is derived from the Greek verb “μαρμαιρω”, meaning “I shine”. In petrography, however, the term refers exclusively to carbonate rocks, consisting of calcite, which have undergone a process of metamorphism and therefore concerns only white marbles.
It was between the Late Republic and the First Empire that the use of marble, both white and polychrome, became a precious instrument of ostentation of personal prestige by local elites. In the aristocratic domus, in the late republican age, mainly the rooms destined to the reception were embellished by such materials, especially in the form of columns.
Among the first cases of use, there are the monolithic threshold in ancient yellow marble of the house of Marco Emilio Lepido of 68 B.C., and the wall covering in lunense and caristio marble of the house of Mamurra on the Celian hill (I cent. B.C.), which represents the first use of marble slabs. The monolithic columns in the atriums of the houses were closely linked to the desire to open the public part of those buildings to the clientele, as a fundamental tool of political struggle. Between the II and the I cent. B.C., the Roman conquest of many regions of the Mediterranean, in particular Greece, Asia Minor and Egypt, favored the exploitation by the Romans of the white and colored marble quarries located in these territories.
The exploitation became intensive during the princedom of Augustus, to the point that Suetonius, biographer of the emperor, testifies to how Rome had become a “marmoream Urbem”. The use of marble, and in particular colored marble, played a significant role in the imperial ideology of Augustus (and his successors). In endowing the city with such precious materials, he intended not only to provide it with a monumental apparatus suited to its new status, but also to redistribute the wealth accumulated during the civil wars, through the promotion of demanding public works.
The Romans selected different marbles, particularly the coloured ones, not only on the basis of their aesthetic value, but also for the physical-mechanical properties they possessed in view of their final destination in the buildings. Particular lithotypes were sought and their choice marked differences in status. The most expensive qualities were a prerogative of the upper classes or only of the imperial family (as in the case of red porphyry; see the sarcophagus of Helena, mother of Constantine I), while the less wealthy had to resort to cheaper lithotypes or marbles called “of replacement”, an important category of coloured materials, resembling aesthetically to the varieties extracted in the most remote and precious imperial quarries, but whose location of extraction was much closer to that of use, as in the case of different types of grey granite.
In public monuments and Roman domus, besides the columns and the covering slabs (both parietal and paving), basins, capitals and various architectural elements were the artifacts for which white and especially coloured marbles were mainly used.
As early as the 4th-5th century A.D. and later throughout the Middle Ages, the polychrome marbles used in ancient architecture were often stripped to be reused in various forms in churches and private residences.