History of Ancient Pottery: Greek, Etruscan, and Roman....

The Romans divided the manufacture of objects in clay into two classes: opus figlinum or fine ware, made from argilla or creta figularis; and opus doliare, for tiles and common earthenware.[2395] We begin, then, as in the chapter on the Greek uses of clay, with the latter division, including the use of this material in Roman architecture, and primarily in the making of bricks and tiles. It must be borne in mind, however, that the structural use of bricks of clay, such as we employ at the present day, was unknown to the Romans; they only used what we should call tiles, and even these were only employed structurally, as a facing to walls and vaults of concrete; no walls were ever built of solid brick, and even in those of seven inches thickness the bricks are built on a core of concrete. Nor were the bricks allowed to appear on the outer face of the building, at least before the second century of the Empire; they were always faced with a coating of marble or stucco.

Nevertheless, the general use of bricks or tiles was most extensive, and they were employed as tiles for roofing houses, as bricks for walls and vaults, and even for columns, as slabs for pavements, for furnaces and for covering graves, and in tube form for conveying water or hot air; they are found in temples, theatres, and baths, and are used for cisterns and fountains, and in aqueducts and military fortifications. They were called lateres, because, says Isidorus, “they were broad, and made by placing round them four boards.”[2396] The kilns were called laterariae, and the makers laterarii; to make bricks was lateres ducere, fingere,[2397] or (with reference to the baking only) coquere. The word later seems to be employed indiscriminately for sun-dried (crudi) and baked bricks (coctiles),[2398] without the qualifying epithet, but testa is also used when burnt brick is intended.[2399] The sun-dried bricks were the earlier and simpler form, used for building walls and cemented together with clay or mud.[2400] Vitruvius in his account of brick-making (ii. 3) only refers to this kind, and apparently never mentions baked bricks except in passing allusions. He describes three kinds, to which he says the Greeks gave the respective names of genus Lydium, pentadoron, and tetradoron (see Vol. I. p. 95).

The two latter are exclusively Greek, but the first-named, 1½ by 1 foot in dimensions, answers to the Roman tegula sesquipedalis.[2401] A frequent arrangement, he says, was to employ half-bricks in alternate courses with the ordinary sizes, which served to bind the walls together and present an effective as well as a stable appearance. This information is repeated by Pliny, copying almost word for word.[2402]

Among the Romans two dimensions were in general use, as may be inferred from the frequent mention in inscriptions or elsewhere of the sesquipedales and of bipedales,[2403] or two-foot bricks, as we shall have occasion to show later. Being very flat and thin in proportion to their size, these bricks rather resemble tiles, as has been already noted; they are generally square, or at least rectangular. But there were also tegulae bessales or bricks measuring two-thirds of a foot square, i.e. about 8 inches, and triangular bricks, equilateral in form, with a length varying from 4 to 14 inches. The latter are the kind used in all existing Roman walls of concrete with brick facings. The thickness varies from 1¼ to 2 inches. They are not always made with mechanical accuracy, the edges being rounded and the sides not always parallel. In military works they were often used alternately with flint and stone (see below, p. 337), as we see them in England, at Colchester, Dover, Verulam, and many other places.[2404] At Verulam the tiles are arranged in three horizontal layers at intervals of about 4 feet, with flint and mortar between. They were also used for turning the arches of doorways, and for this purpose tegulae bipedales were cut into pieces, so as only to tail a few inches into the concrete which they cover. Complete squares were introduced at intervals to improve the bonding.[2405]

The pillars of the floors of hypocausts were formed of tegulae bessales, and sometimes also of two semicircular bricks joined so as to form a circle, varying from 6 to 15 inches in diameter.[2406] Occasionally the upper bricks diminished in size, in order to give greater solidity to the structure. The bricks or tiles forming the upper floors were from 18 to 20 inches square; in some cases, as at Cirencester,[2407] these were flanged tiles (see below).

The general size of Roman bricks was, in the case of the sesquipedales, 1½ by 1 Roman foot; but variations are found, such as 15 by 14 inches. For the bipedales Palladius recommends 2 feet by 1 foot by 4 inches. The great building at Trier known as the Palace of Constantine is built of burnt bricks, 15 inches square by 1¼ inch thick.[2408] Prof. Middleton notes tiles in Rome of 12, 14, and 18 inches square,[2409] and Marquardt[2410] states that bricks found in France measure 15 by 8 to 10 inches; others (the bessales) 8 by 8 by 3 inches. A complete circular brick, measuring 7½ inches across by 3¼ inches thick, and impressed with the stamp of the eleventh legion, was found at Dolae near Gardun, and is now in the museum at Spalato.[2411]

Vitruvius[2412] gives elaborate instructions about the preparation of the clay for sun-dried bricks, and counsels in the first place a careful choice of earth, avoiding that which was sandy or stony or full of loose flints, which made the bricks too heavy, and so liable to split and fall out when affected by rain; it also prevented the straw from binding properly. Clay which was either whitish or decidedly red (from a prevalence of ochre) was preferred, and that combined with coarse sand (sabulo masculus) made light tiles, easily set. The process of manufacture was a very simple one. The clay was first carefully cleaned of foreign bodies, and then moistened with water and kneaded with straw. It was then moulded by hand or in a mould or frame of four boards, and perhaps also pressed with the foot.[2413] The bricks were then dried in the sun and turned as required, the usual process also adopted in the modern brickfield. Some bricks actually bear the marks of the feet of animals and birds which had passed over them while the clay was soft, and there is one in the Shrewsbury Museum with the imprint of a goat’s feet. Others at York and Wiesbaden show the nails of a boy’s shoes.[2414] These impressions of feet (where human) may also be referred to the practice of using the feet to knead the bricks.

The bricks were then ready for use, but were kept for two years before being employed, otherwise they were liable to contract, which caused the stucco to break off and the walls to collapse. At Utica, Vitruvius tells us, they had to be kept five years, and then could only be used if passed by a magistrate. Altogether, much care was taken in their preparation, and it was generally considered that spring and autumn were the most favourable times for making them, probably because they dried more slowly and were less liable to crack during the operation. In summer the hot sun baked the outer surface too fast, and this appeared dry while the interior was still moist, so that when the inside dried the outside contracted and split.[2415] It was also, of course, advisable to avoid seasons of rain and frost. But the bricks could not be properly tested until they had undergone some exposure to the weather, and for this reason Vitruvius recommends the employment of old roof-tiles where possible in building walls.[2416]

For baked bricks the processes must have been much the same, with, of course, the addition of the baking in the furnace. Existing Roman bricks are nearly always of well-tempered clay and well baked; but the clay exhibits a great variety of colour—red, yellow, and brown. The paste is remarkably hard, breaking with an almost vitreous fracture, and sometimes shows fragments of red brick (pozzolana) ground up with it to bind it together, and prevent warping. This may be seen in the Flavian Palace on the Palatine, and in an archway in the Aurelian Wall near the Porta Latina. As an instance of varieties of brick found in the same building, Nero’s Aurea Domus may be cited.[2417] The durability of Roman tiles is ascribed to their careful preparation and seasoning, which give them a much longer life than modern tiles; hence they were frequently used up again in early mediaeval buildings and in Romanesque churches in England, as at St. Albans, St. Mary-in-Castro, Dover, and St. Botolph’s and Holy Trinity, Colchester.[2418]

During the period of the Republic private houses and public buildings alike were built of unburnt brick in Rome, as we learn from the words of Dio Cassius,[2419] Varro,[2420] and Cicero[2421]; Varro speaks of domus latericiae, and Cicero of “the brick (latere) and concrete of which the city is constructed.” After the Republican period this material was still employed outside Rome with burnt-brick cornices,[2422] but even this was exceptional. Pliny mentions walls of sun-dried bricks at Arretium and Mevania.[2423] Henceforth, then, burnt brick was employed more and more as Rome grew more populous.[2424] In Vitruvius’ time (the beginning of our era) the materials used for building were stone for substructures, burnt brick (structura testacea) for the outer walls, concrete for the party-walls, and wood for the roofs and floors. He explains the cessation of the use of unburnt brick as due to the legal regulations of his time, which prohibited party-walls of more than 1½ foot in thickness, and unburnt bricks could only support one story above them in that size.[2425]

Baths, either public or private, walls and military fortifications, were built of bricks, the latter being thus better able to resist attacks than if they were of stone. Temples, palaces, amphitheatres, the magnificent aqueducts and the cisterns with which they communicated, were also usually of this material. Of these, numerous remains exist in Rome and other places, such as Cumae and Pozzuoli. The aqueduct made by Nero from the Anio to Mons Caelius is of brick, that of Trajan partly so; the aqua Alexandrina of Severus Alexander (A.D. 229) and that existing at Metz are wholly of brick, and so are the castella or reservoirs made by Agrippa when he constructed the Julian conduit over the Marcian and Tepulan.[2426] It is true that Augustus boasted that he had found Rome of brick and left it marble[2427]; but it must be remembered, firstly, that Suetonius uses the term latericiam, which may denote unburnt brick; secondly, that the phrase is probably to be limited to public buildings and monuments, in which there was an increased use of marble for pillars and roofs. For walls brick and concrete continued to be used, as in private buildings, with a covering of stucco in place of marble incrustation.

In the first century of the Empire brick-making was brought to perfection, and its use became universal for private and public buildings alike; the mortar of the period is also of remarkable excellence. The Romans introduced brick-making wherever they went; and even their legions when on foreign service used it for military purposes. But of pure brick architecture, as we see it, for instance, in the Byzantine churches of Northern Italy, there was no question until comparatively late times. It was always covered over with marble or stucco until the second century of the Empire. Examples of sepulchral buildings wholly in brick, of the time of Hadrian, may be seen in the tomb before the Porta San Sebastiano at Rome, known as the temple of Deus Rediculus. This has Corinthian pilasters with a rich entablature, red bricks being used for architectural members, yellow for the walls; the capitals are formed of layers of bricks. Of Hadrian’s time are also the guard-house of the seventh cohort of Vigiles across the Tiber, of which a small part remains, and the amphitheatrum castrense on the walls of Aurelian.[2428]

One of the most remarkable instances of Roman brick construction is the Pile Cinq-Mars, as it is called, a tower still standing on the right bank of the Loire, near Tours. It is about 95 feet high and 13 feet square, expanding at the base, being built of tiles to a depth of 3 feet each side, with a body of concrete; the tiles are set in mortar composed of chalk, sand, and pounded tiles. On one side there are eleven rectangular panels with tile-work of various patterns, like those on the flue-tiles (see p. 348), and as also seen on the Roman wall at Cologne; the patterns include squares, triangles, and rosettes. The history and purpose of this building are quite unknown.[2429]

At Pompeii bricks are used only for corners of buildings or doorposts, and sometimes for columns, as in the Basilica and the house of the Labyrinth.[2430] There are also late examples of brick columns with capitals in tiers of bricks as in the tomb mentioned above. Brick walls are not found, but bricks occur as facing for rubble-work. These are less than an inch thick, triangular in form, with the hypotenuse (about 6 inches long) showing in the face of the wall. Sometimes fragments of roof-tiles are used (cf. p. 334). The earlier bricks contain sea-sand, and have a granular surface; the later are smooth and even in appearance. Later, what is known as opus mixtum (see below) is used, as in the entrance of the Herculaneum gate; this implies courses of stone and brick alternating,[2431] which, as we have seen, was common in military works, as in the Roman walls in Britain. In this country, owing to the absence of good material for concrete, the use of stones or brick throughout for building was general from the first; hence, too, the bricks are always flat and rectangular in form (bipedales).[2432]

The arrangement of triangular bricks (made by dividing a medium-sized brick into four before baking), laid flat in regular horizontal courses, is characteristic of the earliest examples of Roman methods. It is found in the Rostra (44 B.C.) and in the Regia (35 B.C.), the earliest existing examples.[2433] The back wall of the Rostra is of concrete faced with triangular bricks 1½ inch thick, the sides 10 inches long. The same arrangement may be seen in the Pantheon, in the Thermae of Diocletian, and in some of the aqueducts (see below). The brickwork in the Pantheon was formerly thought to belong to the building of Agrippa in 27 B.C., but has been now shown to belong to the second century.[2434] At Ostia, in the temple of Honos and Virtus, the walls are built of triangular bricks or with red and yellow bricks with moulded cornices.

About the year 80 B.C. the method known as opus reticulatum was introduced, in which the bricks presented square faces (about 4 inches each way), and were arranged diagonally to form a network pattern (Fig. 187). At Pompeii the opus reticulatum dates from the time of Augustus; it is laid on concrete, and the bricks are small four-sided pyramids with bases 3 to 4 inches square.[2435] This method lasted down to about A.D. 130 in Italy. It should, however, be noted that it was commoner in stone than in brick, the latter material not having come into general use for building at the time when it was employed.[2436] But even when tufa was used for the reticulated work, bricks or tiles were used for quoins at the angles, and for bonding courses through the walls, as well as for arches and vaults (Fig. 188). This combination of opus reticulatum and brickwork is well illustrated in the palace of Caligula.[2437] In the case of vaults, indeed, the use of brick seems to have been general, as in the baths of Caracalla, and many other buildings (cf. Fig. 189). Vitruvius[2438] advises the use of tegulae bipedales to protect the wooden joists over the vaults from being rotted by the steam from the hot bathrooms; they were to be placed over the whole under-surface of the concrete vault, supported on iron girders, which were suspended from the concrete by iron clamps or pins. Over the whole was laid a coating of cement (opus tectorium) in which pounded pottery was the chief constituent, and this was stuccoed.[2439]

The opus mixtum (the term is not classical) prevailed regularly under the later Empire, from the fourth to the sixth century; the earliest example which can be dated is the circus of Maxentius. It is also used in work of the time of Theodoric.[2440] The method of construction is shown in Fig. 190.

The reason for the limited use of brick in Rome may have been the scarcity of wood for fuel for the kilns. But in any case the pointed backs of the bricks made a good bonding with concrete, and presented a large surface with a comparatively small amount of clay. The secret of the wonderful durability of Roman buildings is that each wall was one solid coherent mass, owing to the excellence of the concrete. In the Pantheon the concrete of the dome is nearly 20 feet thick, the brick facing only about 5 inches. The character of the brick facing often indicates the date of a wall, the bricks in early work being thick and the joints thin; later, the reverse is the case. But caution must be exercised in dating on this principle, owing to the great variety of methods employed during the same reign, and even in the same building.[2441]

The word for a tile, tegula, is derived from tegere, to cover, or, as Isidorus says, they are so called quod aedes tegant[2442]; the curved roof-tiles were known as imbrices because they received rain-showers (imbres). The maker of roof-tiles was known as tegularius[2443] or figulus ab imbricibus.[2444] Tegulae or flat roof-tiles were usually made with vertical flanges (2½ inches high) down the sides, and these flanges, which fitted into one another longitudinally, when placed side by side served to hold the covering-tiles placed over them. There were also roof-tiles known as tegulae deliciares[2445] and colliciares, which formed the arrangement underneath the surface of the roof by means of which the water was collected from the tegulae and carried off in the front through spouts in the form of lions’ heads.[2446]

Besides the various rectangular forms we find triangular tiles used, either equilateral or right-angled; semicircular or curved tiles, used for circular walls, ovens, tombs, and cornices, or other parts of buildings; cylindrical tiles (tubuli fictiles),[2447] which were used for drains and conduits; and, finally, the rectangular hollow flue-tiles, employed for hot air in hypocausts.[2448] Another form was the tegula mammata, a plain square tile with four knobs or breast-like projections (mammae), which was often used in party-walls with the object of keeping out damp.[2449] The tiles were inserted by the points of the projections into the concrete, thus leaving a space between in which the warm air could circulate freely.

Existing examples of tiles are composed of a compact dense clay, less fine than that of the bricks, and of a pale salmon or light straw colour when baked. They were probably made in moulds—but these may only have been a couple of boards placed together—and after being dried in the sun were baked in kilns. The flanged tiles were, of course, produced by turning up the edges before drying. Besides the arrangement described above, it is probable that roofs were sometimes tiled in the manner prevalent in the present day, with flat or curved tiles overlapping like scales; and for this purpose the tiles seem to have been pierced with holes at one corner, and so attached to one another. The same method obtained in the Roman villas in Britain, except that Stonesfield slate was used in place of tiles. An inscription found at Niederbrunnen in Germany speaks of attegia tegulicia, or huts roofed with tiles, erected in honour of Mercury.[2450]

Tiles with turned-up edges or flanged tiles were principally employed, as has been indicated, for roofing; but some were also placed in walls where required, especially where a space was required for the passage of air.[2451] They were also employed for the floors of bath-rooms, in which case they were laid on the pilae of the hypocaust in an inverted position, and the cement flooring was laid upon them. The flanges are generally about 2¼ inches higher than the lower surface of the tile; they are bevelled on the inner side in order to diminish the diameter of the imbrex, but have no holes for nailing to the rafters. The ends of the sides were cut away in order that the lower edge of one tile might rest on the upper edge of the one adjoining. Those found in France are said to be distinguished by the sand and stones found in their composition.[2452] There are flange tiles of red and yellow clay from the Roman Thermae at Saintes in the Museum of Sèvres, and others from ancient potteries at Milhac de Nontron, as well as tiles of red clay from Palmyra.[2453] In the military castra in England flange tiles of a red or yellow colour have been found, the latter with fragments of red tiles mixed in the clay. They are also often found in the ruins of villas. A flange tile from Boxmoor, Herts, now in the British Museum, measures 15½ by 12 inches, the flange being 2¼ inches high; and it will be seen that these dimensions correspond roughly with the tegulae bipedales.

The imbrices or covering-tiles which held the flat tiles together, thus rendering the roof compact, were quite plain, with the exception of the end ones over the gutters. These were in the form of antefixal ornaments like the Greek examples (Vol. I. p. 98), an upright semi-oval termination ornamented with a relief or painted pattern, with an arched support at the back. Many examples exist at Pompeii (see below), Ostia,[2455] and elsewhere; but artistically they are far inferior to the Greek examples, and of simpler design. Most of them have a simple palmette or acanthus pattern in low relief, but on or below this an ideal head or the head of a deity is sometimes added, such as Zeus Ammon, Medusa, a Bacchic head, or a mask, or even a figure of Victory. Of the last-named there is a good specimen in the British Museum (D 690 = Fig. 191); she carries a trophy from the battle of Actium, and stands on a globe from which spring two Capricorns (the symbol of Augustus).[2456]

No better example of the various uses of ornamental tiles in architecture can be selected than the remains found at Pompeii, which are exceedingly numerous. Terracotta seems to have been used here especially for such parts of the decoration as were exposed to wet, as well-mouths, gutters, and antefixal tiles.[2457] A characteristic feature of the decoration of Pompeian houses was the trough-like gutter which surrounded and formed an ornamental cornice to the compluvium or open skylight of the atrium and peristyle, through and from which the rain-water was collected in the impluvium or tank sunk in the ground below. These were adorned with spouts in the form of animals’ heads or foreparts,[2458] usually lions and dogs, with borders of palmettes between; the gutter behind was virtually a long tank of square section.

Antefixes and gutter-cornices, where they occur, must always be regarded as serving ornamental rather than necessary purposes. All early work in terracotta at Pompeii is of coarse clay, but good execution; later, the reverse is the case. The only public building in which many remains of terracotta tiles and cornices have been preserved is the temple of Isis; but the Basilica may also have had terracotta decoration. Many fragments also remain from private houses, some actually in situ, having been neglected by early explorers as unimportant. In the house of Sallust a kymation cornice from one of the garden courts has scenic masks forming the spouts; this is not earlier than the rebuilding of the house A.D. 63. There is also much terracotta work in the house of the Faun.[2459] Comic masks were used both as spouts and as antefixes, the exaggerated mouth of the mask serving admirably for the former purpose.[2460] These date from the reigns of Nero and Vespasian, and all seem to be from the same fabric, although there is considerable variety in the types; the use of masks for these purposes is not earlier than Nero’s reign (cf. the house of Sallust, above). Besides the ornaments above mentioned the patterns on the cornices include palmettes and floral scrolls, dolphins and Gryphons.

The roof-tiles were of the usual kinds, flat oblong tegulae with flanges, measuring 24 by 19 by 20 inches,[2461] with semi-cylindrical imbrices. They were laid in lines parallel to the long ridges of the roofs, so that the water converged into the gutter-tiles at the angles, whence it fell into the impluvium. These gutters, however, were not confined to the angles of the openings, but were sometimes ranged along the whole length of the sides, as we have seen; those at the angles only seem to be earlier in date. They are not found on the exteriors of buildings. The front of the gutter was usually in the form of a vertical kymation moulding, but was sometimes simply chamfered. Antefixal ornaments terminating the covering or ridge-tiles are not invariable, but are found at different periods. The earliest examples are in the form of palmettes, but the later exhibit a great variety[2462]: comic masks, a head in low relief on a palmette, or a head surmounted by a palmette. Of the latter class thirty-eight were found in 1861. In the Augustan period ideal heads of gods and demi-gods are sometimes found.[2463]

Von Rohden, in summing up (p. 14), is of the opinion that terracotta roof-decoration at Pompeii was comparatively rare. In the whole record of excavations only twenty-three water-spouts are mentioned, though it is probable that many were never registered. In scarcely more than twelve private houses have as many pieces been found as would suffice for the whole of the atrium and peristyle roofs, and nearly all of these are of late date. The discovery of isolated pieces in a house seems to show that they were used up again in the restorations after the earthquake of A.D. 63.

There are also some good examples of roof-tiles among those which have been found at Ostia, both in baths and private houses; some of the latter came from a house of which the brickwork bore inscriptions with the names of consuls of Hadrian’s reign. The arrangement of the roof-tiles is that described on p. 341; the antefixal ornaments are usually in the form of palmettes or acanthus leaves, with maeander below; but heads of deities, such as Venus and Neptune,[2464] or of Medusa, and tragic masks were also found. Two exceptional examples had groups in relief of Neptune drawn over the sea by hippocamps, and of the statue of Cybele in the ship drawn by the Vestal Virgin Claudia.[2465]

Tiles of the size known as bipedales are also used for lining the walls of rooms. They are found in Roman villas in Britain, and are ornamented on one side with various incised patterns, made with a tool in the wet clay. On some found at Ridgewell in Essex the decoration consists of lozenges, rosettes, and other ornaments,[2466] like those on the Pile Cinq-Mars already described; they are often found covered with the stucco with which the walls were plastered. At Pompeii, Orvieto, and elsewhere the stucco-painted walls were constructed with tegulae mammatae placed edgewise, and connected with the main walls by leaden cramps, the brick lining being thus detached from the walls by a narrow interval which served as an air-cavity.[2467] This was a frequent proceeding, and was also contrived with flanged tiles; it corresponds with the system prescribed by Vitruvius for keeping damp from the painted walls of rooms.[2468] It was also largely employed in baths and bathrooms, the object being both to keep the walls dry and to allow hot air to circulate from the hypocausts and warm the rooms. In the cold climate of Britain the Romans found this a universal necessity, and instances may be observed in many of their villas; but, as far as can be observed, the general method of warming was by an extensive system of pipes under the floors rather than up the walls.[2469] These tiles are pierced with holes, by means of which they were attached to the walls by plugs or nails of lead.