It is right, first, to explain that in this dissertation we shall make constant use of two or three words borrowed from foreign languages; one is botega or bottega, implying something between a workshop and an artist’s studio, which it would be difficult to express by a single English word: another is fabrique, meaning the private establishment of a master potter of that day, the idea of which cannot be so well conveyed by factory, pottery, or studio (itself an imported word), all of which are therein combined and modified.
The history of pottery and its manufacture is a subject of great extent; because from a very early period of human existence, known to us only by the tangible memorials of primitive inhabitants, the potter’s art appears to have been practised. At first the vessels were of coarse clay, rude and sun-dried or ill-baked, and occasionally ornamented with concentric and transverse scratches; from which state they gradually developed to the exquisite forms and decoration of the Greek pottery; but it would seem that however universal the production of vessels of baked clay, the art of applying to them a vitreous covering or glaze was an invention which emanated from the east, from India or Egypt, Assyria or Babylon.
On this point Dr. Birch, in the introduction to his erudite work on ancient pottery, says: “The desire of rendering terra-cotta less porous, and of producing vessels capable of retaining liquids, gave rise to the covering of it with a vitreous enamel or glaze. The invention of glass has hitherto been generally attributed to the Phœnicians; but opaque glasses or enamels as old as the eighteenth dynasty, and enamelled objects as early as the fourth, have been found in Egypt. The employment of copper to produce a brilliant blue coloured enamel was very early, both in Babylonia and Assyria; but the use of tin for a white enamel, as recently discovered in the enamelled bricks and vases of Babylonia and Assyria, anticipated, by many centuries, the re-discovery of that process in Europe in the fifteenth century, and shows the early application of metallic oxides. This invention apparently remained for many centuries a secret among the eastern nations only, enamelled terra-cotta and glass forming articles of commercial export from Egypt and Phœnicia to every part of the Mediterranean. Among the Egyptians and Assyrians enamelling was used more frequently than glazing, and their works are consequently a kind of fayence, consisting of a loose frit or body, to which an enamel adheres, after only a slight fusion. After the fall of the Roman empire the art of enamelling terra-cotta disappeared among the Arab and Moorish races, who had retained a traditional knowledge of the process. The application of a transparent vitreous coating or glaze over the entire surface, like the varnish of a picture, is also referable to a high antiquity, and was universally adopted, either to enhance the beauty of single colours or to promote the combination of many. Innumerable fragments and remains of glazed vases, fabricated by the Greeks and Romans, not only prove the early use of glazing, but also exhibit in the present day many of the noblest efforts of the potter’s art.”
It is true that on the Greek, Etruscan, and Roman pottery a subdued and hardly apparent glazing was applied to the surface of the pieces, but it is so slight as to leave a barely appreciable effect upon the eye, beyond that which might be produced by a mechanical polish, and so thinly laid on as almost to defy attempts at proving its nature by chemical investigation; it is, however, supposed to have been produced by a dilute aluminous soda glass, without any trace of lead in its composition, the greater portion of which was absorbed into the substance of the piece, thereby increasing its hardness and leaving only a faint polish on the surface of the ware.
In Egypt and the east the use of a distinct glaze (invetriatura of the Italians), covering the otherwise more porous substance of the vessel, appears to have been known and to have arrived at great perfection at a very remote period. It was in fact a superior ware, equivalent to the porcelain of our days, and from the technical excellence of some of the smaller pieces has been frequently, but wrongly, so called.
It will perhaps be as well, before entering further into the consideration of the subject, to define and arrange the objects of our attention under general heads.
Pottery (Fayence, Terraglia), as distinct from porcelain, is formed of potter’s clay mixed with marl of argillaceous and calcareous nature, and sand, variously proportioned, and may be classed under two divisions: Soft (Fayence à pâte tendre), and Hard (Fayence à pâte dure), according to the nature of the composition or the degree of heat under which it has been fired in the kiln. What is known generally in England as earthenware is soft, while stone ware, queen’s ware, &c. are hard. The characteristics of the soft wares are a paste, or body, which may be scratched with a knife or file, and fusibility, generally, at the heat of a porcelain furnace.
These soft wares may be again divided into four subdivisions: unglazed, lustrous, glazed, and enamelled. Among the three first of these subdivisions may be arranged almost all the ancient pottery of Egypt, Greece, Etruria, and Rome; as also the larger portion of that in general use among all nations during mediæval and modern times. We shall be occupied with the glazed and enamelled wares: the first of which may be again divided into siliceous or glass glazed, and plumbeous or lead glazed.
In these subdivisions the foundation is in all cases the same. The mixed clay or “paste” or “body” (varied in composition according to the nature of the glaze to be superimposed) is formed by the hand, or on the wheel, or impressed into moulds; then slowly dried and baked in a furnace or stove, after which, on cooling, it is in a state to receive the glaze. This is prepared by fusing sand or other siliceous material with potash or soda to form a translucent glass, the composition, in the main, of the glaze upon siliceous wares. The addition of a varying but considerable quantity of the oxide of lead, by which it is rendered more easily fusible but still translucent, constitutes the glaze of plumbeous wares: and the further addition of the oxide of tin produces an enamel of an opaque white of great purity, which is the characteristic glazing of stanniferous or tin-glazed wares. In every case the vitreous substance is reduced to the finest powder by mechanical and other means, being milled with water to the consistency of cream; into this the dry and absorbent baked piece is dipped and withdrawn, leaving a coating of the material of the bath adhering to its surface. A second firing, when quite dry, fuses this coating into a glazed surface on the piece, rendering it lustrous and impermeable to liquids. The two former of these glazes may be variously coloured by the admixture of metallic oxides, as copper for green, iron for yellow, &c.; but they are nevertheless translucent, and show the natural colour of the baked clay beneath.
Vitreous or Glass-Glazed Wares.
The vitreous, silico-alcaline or glass-glazed wares, were of very ancient date and in all probability had their origin in the east, in Egypt, or India, or Phœnicia; indeed the discovery of glass, which has always been attributed to the latter country, would soon direct the potter’s attention to a mode of covering his porous vessel of baked earth with a coating of the new material; but the ordinary baked clay would not take or hold the glaze, which rose in bubbles and scaled off, refusing to adhere to the surface, and it became necessary to form the pieces of a mixed material, consisting of much siliceous sand, some aluminous earth, and probably a small portion of alcali, thus rendering it of a nature approximating to that of the glaze, and to which the latter firmly adhered. In some instances, on the finer examples which may probably have been exposed to a higher temperature in the oven, the glaze and the body of the piece have become so incorporated as to produce a semi-translucent substance, analogous to some artificial porcelains. In its nature this glaze is translucent, and accordingly we find that when ornamented with designs, they are executed directly on the “biscuit” or unglazed surface of the piece, which then receives its vitreous covering through which they are apparent. By means of an oxide of copper the exquisite turquoise blue of ancient Egypt, “scarcely rivalled after thirty centuries of human experience,” was produced. The green colour was, perhaps, given by means of another oxide of the same metal; violet by manganese or gold, yellow by silver or perhaps by iron, and the rarer red perhaps by the protoxide of copper. We also find that bricks and vases of similar glazing, brought to its greatest perfection in Egypt, were made by the Babylonians and Assyrians.
Throughout Babylonia the sites of ancient buildings afford fragments of glazed pottery. The glaze of those brought from Borsippa by the abbé Beauchamp, in 1790, was analysed and found to contain neither the oxides of lead nor tin, but to be an alcaline silicate with alumina, coloured by metallic oxides. A more recent analysis of Assyrian examples shows that with a base of silicate of soda or soda glass and oxide of tin the opaque white has been produced, being the earliest recorded example of “enamelled” ware. A small quantity of oxide of lead was also found in the blue glaze on tiles from Babylonia. At Warka, probably the ancient Ur of the Chaldees, Mr. Loftus discovered numerous coffins or sarcophagi, piled one upon another to the height of forty-five feet, of peculiar form, and made of terra-cotta glazed with a siliceous glaze of bluish-green colour. They are formed somewhat like a shoe, an opening being left at the upper and wider end for the insertion of the body, and closed by an oval lid which, as well as the upper part of the coffin, is ornamented with figures and plants in relief. They are supposed to be of the Sassanian period.
The metallic lustre in decoration was applied, apparently at an early time, to pottery glazed with a siliceous coating, and appears to have established itself in Persia. On specimens from Arabia it is also found, and its use in combination with this glaze may possibly have preceded the manufacture of lustred wares coated with the stanniferous enamel, by the eastern potters of the Balearic islands, Spain, and Sicily.
In northern India, at Sind, and in Persia, wares are made at the present day of precisely the same character as the ancient pottery under consideration. Pieces from the former locality, which were exhibited at the International Exhibition of 1871, are composed of a sandy argillaceous frit, ornamented with pattern in cobalt blue beneath a siliceous glaze. Indeed their agreement in technical character with some of the pottery of the ancient Egyptians and Assyrians, and with that produced in Syria and Persia during the fourteenth, fifteenth, and sixteenth centuries, is most remarkable. Persia also now produces inferior wares of the same class, specimens of which, as well as some of those from India, are preserved in the South Kensington museum: the engraving on the opposite page represents a wall tile (no. 623) of the seventeenth century.
We thus see how widely spread, and at how early a period, the use of this most ancient mode of glazing was established and brought to perfection. It was the parent of all those wares now known as Persian, Damascus, Rhodian, or Lindus.
Plumbeous, or Lead Glazed Wares.
The silico-plumbeous or lead-glazed wares were for many ages and still are the most common, and, in Europe, the most widely spread class of pottery: indeed, throughout the northern and western countries lead, in combination with glass, seems to have
been the earliest and until the fifteenth century the only means known of glazing soft pottery.
We have seen that a certain amount of lead has been found in some of the blue coloured glazes of Babylonia, and (says Dr. Percy) “probably employed as a flux;” if so, this might have been the spring of its general adoption for the purpose of producing a more easily fusible and therefore a more ready and more manageable coating; but in the east it does not seem to have supplanted the more elegant and purer siliceous glaze.
Fragments of Græco-Roman pottery from Tarsus, lamps from the neighbourhood of Naples, and other examples of a highly glazed pottery from various antique sites which have all the appearance of a plumbeous composition, are preserved in many collections, as at the Louvre, Naples, the British museum, &c. The paste of which these examples are formed is to all appearance an ordinary potter’s clay, generally of a buff colour, and in no way similar in character to that of the Egyptian or Assyrian wares, glazed with a true glass. The adhesion of the vitreous coating to the surface, and its perfect adaptability to the irregularities of the shaped and moulded pieces, prove its affinity for the paste of which they are made, and indirectly that its composition is not the same as that of the Egyptian or Assyrian glaze.
It is worthy of remark that nearly all these specimens are found in the south of Europe, examples rarely occurring even at Rome; and, indeed, it is not improbable that the use of this glaze had hardly been adopted by the artistic potters before their art, together with all others, had degenerated under the Lower Empire. The superabundance of the precious metals and other rich material, more appreciated by the powerful than the priceless treasures which art had formed from common clay, and which had been the delight of a more refined state of society, led finally to a total neglect of the higher branches of ceramic manufacture.
It is not unlikely that plumbeous glaze may have been introduced by Greek or oriental potters into southern Italy. We learn from the monk Theophilus that the art of decorating fictile vessels with vitreous colours was practised by the Byzantine Greeks, who would have carried it there. This statement, in all probability, refers to the lead glazed wares and not to the tin enamel, the former of which, as we have seen, was known earlier than his time to the potters of Tarsus, Pompeii, &c., and it is reasonable to believe that the art may have been preserved in Byzantium when lost, or nearly lost, in Italy. Perhaps, in combination with incised ornament the use of this glaze never ceased in that country from the eighth and ninth centuries until the introduction or discovery of the stanniferous enamel in the fifteenth century; and we find that the earliest glazed wares of that country, the sgraffiati, the painted, and the mezza maiolica wares, are covered with this description of vitreous surface.
In the eleventh century churches built in various places were decorated with discs and “ciotole” of glazed and painted terra-cotta. The researches of the abbé Cochet at Bouteilles have shown that glazed pottery was in use in the north of France in the Anglo-norman period of the thirteenth and fourteenth centuries, or perhaps even in earlier time. Examples of glazed and painted tiles of the fourteenth century are preserved in the British museum. As before stated, this glaze is composed of silica with varying proportions of potash or soda and of oxide of lead, by which addition it is rendered more easily fusible but remains transparent.
To obtain a white surface was, however, desirable, the colour of the paste beneath the glaze being generally of a dull red or buff and ill-adapted as a ground for the display of coloured ornamentation. To supply this want, before the invention of the tin enamel, an intervening process was adopted. A white argillaceous earth of the nature of pipeclay was purified and milled with water, and thus applied over the coarser surface of the piece in the same manner as the glaze: again dried, or slightly fixed by fire, it was ready to receive the translucent coat through which the white “slip” or “engobe” became apparent. It is easy to conceive that by scratching a design or pattern through this white applied surface to the darker clay beneath, before fixing in the fire, a ready mode of decoration presented itself without the use of colour, to be covered with but visible through the glaze; hence the early incised or “sgraffiato” ware, one of the primitive modes of decorating glazed pottery.
Passeri states that pottery works existed from remote periods in the neighbourhood of Pesaro, as proved by remains of furnaces and fragments of Roman time and tiles with the stamp of Theodoric; that during the dark ages the manufacture was neglected, but that it revived after 1300, and that it then became the fashion in that city to adorn the church towers and façades with discs and “bacini” of coloured and glazed earthenware; a practice which had been in use at Pisa and other cities as early as the eleventh century. The origin of this custom has been much discussed; and the reader will find an account of it in the introduction to the detailed catalogue of Maiolica in the South Kensington collection. Occasionally, or rather frequently, circular and square slabs of porphyry and serpentine were used on the same building, concurrently with the glazed earthenware, as on the tower of Sta. Maria Maggiore at Rome; and, indeed, this mode of enrichment attached to the architecture of the 11th, 12th, and 13th centuries is in accordance with that produced by the enamelled discs and inlaid stones on processional crosses and church plate of the same period.
The only instance, observed by the writer, of the occurrence of these “bacini” of glazed ware in domestic architecture is seen over the windows of the palazzo Fava in Bologna. This style of decoration ceased entirely during the course of the fourteenth century.
Passeri instances the use of glaze on tiles upon a tomb in Bologna, opposite the church of S. Domenico, dated about 1100; and he further states, but we know not upon what authority, that it was about the year 1300 that the method of covering the clay with a “slip” or “engobe” of white earth, or the coarser earth of Verona, was first adopted. Slightly baked, it was glazed with “marzacotto” (oxide of lead and glass), applied wet and again fired; and this glaze was variously coloured yellow, green, black, and blue, by iron, copper, manganese, and cobalt. A similar method of coating the rough and porous baked clay seems to have been known also at a very early period in the north of Europe, and to have been in use throughout France, Germany, and England.
Enamelled or Stanniferous Glazed Wares.
It was found that by the addition of a certain portion of the oxide of tin to the composition of glass and oxide of lead the character of the glaze entirely alters. Instead of being translucent it becomes, on fusion, an opaque and beautifully white enamel, the intervening process of covering the surface of the clay with a stratum of white earth before glazing being unnecessary. It, moreover, was found to afford a better ground for the application of coloured ornament. The process of application was the same as for the “slip;” after immersion in the enamel bath, and subsequent drying, the painting is applied upon the absorbent surface; the piece being then subjected to the fire which, at one application, fixes the colours and liquifies the glaze. This “enamelled” pottery (émaillée) is by far the more important group of the glazed wares, being susceptible of decoration by the lustre pigments, as well as by painting in colours of great delicacy; and it comprises the Hispano-moresque, the real Maiolica, and the perfected earthenware of Italy and other countries.
It is true that the first trace of the application of oxide of tin to produce a white opaque glazed surface is to be met with upon Babylonian or Assyrian bricks, but we are disposed to think that it was then merely used as a pigment to produce a white colour, and not as an application to pottery for the production of a white opaque glaze capable of receiving coloured enrichment by painting in other pigments. A corroboration of this opinion would seem to exist in the fact that throughout Asia Minor, Syria, Persia, and Egypt, a purely stanniferous glaze on pottery has never been generally adopted, or taken the place of that simple and beautiful siliceous coating, so dexterously applied and with such richness of effect upon the Persian and Damascus earthenware. Engraved is an example of an early Damascus plate (no. 6590), at South
Kensington. Perhaps isolated and lying dormant in remote localities for centuries, its use may have been learned by the Arabs, for its next appearance is upon fragments of tiling apparently of their manufacture or fashioned under their influence. How the knowledge of this enamel travelled, when and where it was first used, and to what extent applied, is still doubtful. We meet with an occasional fragment generally upon mural decoration of uncertain date on various Arab sites, till at length it becomes palpably appreciable in the Moorish potteries of Spain and of the Balearic islands. The baron J. Ch. Davillier, in his excellent work on pottery, states that he has not been able to discover any piece which could reasonably be ascribed to a date anterior to the fourteenth century, some two hundred years after the expulsion of the Saracens from Spain. In Valencia, however, anterior to its conquest by Jayme I. of Arragon in 1239, potteries had been long established, and were of such importance that that monarch felt himself bound to protect the Moorish potters of Xativa (San Filippo) by a special edict.
We must bear in mind that there were two periods of Mahommedan sway in Spain, the first on the expulsion of the Gothic monarchy by the Arabs and the establishment of the Caliphate at Cordova, in the eighth century. Of the ceramic productions of this early period we have no accurate knowledge, but we should expect to find them of similar character to the siliceous glazed wares prevalent in the east. The second period is after an interval of five centuries, in 1235, when the Moors founded the kingdom of Granada, having driven out the Arabs. Then first appear the wares usually known as Hispano-moresque, like the fine vase (engraved) no. 8968, at South Kensington; for we find the tiles of the Alhambra dating about 1300, the Alhambra vase about 1320, and continuous abundant examples of tin glazed wares of Moorish origin, until the period of the conquest of the country by Ferdinand and Isabella; after which the pottery becomes more purely Spanish and speedily declines.
Mr. Marryat remarks, in reference to the second or Moorish period, that the art of the new invaders had the same origin as the old, but as we have no specimens known to have been of the earlier or Arabian period we cannot accept this verdict as conclusive. Moreover, some confusion has arisen in classing together the glass glazed or siliceous pottery, with or without metallic lustre, and the Moresque wares produced in Spain, which are so distinctly characteristic as being enamelled with the oxide of tin.
We particularly refer to those somewhat rare examples of early siliceous pottery, like the deep Rhodian plate next engraved, some enriched with metallic lustre, others without, the designs upon all of which are eminently Arabian or Saracenic, unreadable mock Arabic inscriptions occurring (as in the textile fabrics of the same period) among the ornaments; as in the thirteenth century vase in the woodcut, p. 17. Such are the tiles of early date from various
places in Persia and Arabia. Similar wares, of which there are specimens at South Kensington, are supposed to have been made by oriental potters in Sicily but it is difficult to say at what time. That island was conquered by the Saracens in 827. Again, there is another variety of pottery of Moresque character and ornamentation with vermicular pattern in copper lustre on a seemingly stanniferous glaze, which is ascribed to Moorish potters who went to Sicily and established works at Calata Girone in the fourteenth century.
It is not improbable that the existence in Spain of tin ores in considerable abundance may have accidentally led to the discovery or to the adoption of the stanniferous enamel, obtained by an admixture of the oxide of that metal with glass and oxide of lead. We have no positive proof of its use on pottery at an earlier date in any other country, since the period of the Babylonian bricks. May there not be some truth in the story of the Majorcan dishes built into the Pisan towers, and that the single specimen of “Persian” ware found by the writer on the church of Sta. Cecilia in that city, which in all probability was placed there early in the twelfth century, may be one of the dishes brought home by the Pisans, at a time anterior to the use of the tin enamel in Majorca?
There is generally a foundation for fabulous stories, and it is not unlikely that some few of those trophies were so applied; the more so as the taste for such architectural decoration prevailed at that period. At the same time there can be no doubt that many of the bacini adorning churches in various parts of Italy, including Pisa, were of native Italian manufacture, as would seem probable from their compositions and designs. Engravings of these, and of the fragment of oriental ware above alluded to, are published in the Archæologia, vol. xlii. We are indebted to the council of the Society of antiquaries for permission (see next page) to use the latter block.
The earliest traces of the use of stanniferous enamel glaze in Europe, known to us, is always in connection with a decoration, produced by the reduction of certain metallic salts in the reverberatory furnace, leaving a thin film upon the surface, which gives that beautiful and rich effect known as reflet métallique, nacré, cangiante, rubino, reverberato, &c., and in England as lustred ware. In Italy the use of a metallic lustre was apparently known and practised previous to the introduction of the tin enamel, for we have abundant examples of early “mezza-maiolica” from the potteries of Pesaro or Gubbio, glazed only with the oxide of lead and glass, and which are brilliantly lustred with the metallic colours. None of these can, however, be referred to an earlier date than the latter half of the fifteenth century.