Mosaics, as a term, according to the usual authorities is derived through generations of gradual change from the Greek mouseion, "appertaining to the Muses." In the later Latin there are the terms opus musivum "mosaic work," musivarius, "mosaic worker," but probably the English word "mosaic" is derived immediately from the French mosaique, which with its earlier form mousaique can only be borrowed from the Italian or Provençal and cannot be the descendant of the earlier French form musike. It is, however, questionable if these terms were applied to all the different species of work which may now be classed as "mosaic", and it is probable that they were only properly applied to the products of the worker in opus tessellatum or vermiculatum, formed of small cubes of glass, marble or other material. If we define mosaic as a collocation of pieces of marble, glass, ceramic material, or precious stone embedded in some species of cement so as to form an ornamental entity, we should have to include the opus Alexandrinum, and other ordinary paintings such as were used for the less dignified portions of Roman houses. The term mosaic would also be made to apply to the opus sectile (Vitruvius, VII, i) made of pieces of marble and glass forming geometrical or foliated patterns, each piece being ground exactly to fit into the design or in the case of pictures, ground to make the shapes necessary for the completion of the subject. We also apply the term to the pavement work of later date, like that in St. Mary Major's in Rome, and that in Canterbury Cathedral and in the sanctuary of Westminster Abbey in England, as well as to mosaics of a miniature species used for jewellery and small pictures such as the Head of Our Lord which was presented by Pope Sixtus IV to Philip de Croy in 1475 and is now in the Treasury of Sts. Peter and Paul's, Chimay. This latter tradition of work still exists, and every visitor to Rome or southern Italy is acquainted with the cheap but wonderfully executed mosaic jewellery which is sold in most of the shops, and even in the streets of Rome. There is little doubt but that mosaic in jewellery is of considerable antiquity.

History

In passing these various species in historical review, the earliest to be mentioned is that in Exodus, a pavement (xxiv, 10) "a work of sapphire stones", and the pavement of Ahasuerus at Susa "paved with porphyry and white marble, and embellished with painting of wonderful variety", which here, probably, means varied inlaid colour since surface painting would be out of place on a pavement. And we may well believe that the Persians knew of tessellated work when we consider the enamelled bricks, which may be called a large kind of "tessellatum," now in the Louvre from this same palace at Susa. This is the only record earlier than the existing examples in the Roman pavements of the Republic and Empire such as remain in the Regia, the Temple of Castor, the House of Livia, Pompeii, etc. Suetonius says that Caesar was accustomed to carry in his campaign both tessellated and sectile pavements. It appears according to Pliny (XXXVI, i) that in the theatres and basilicas, as well as in certain palaces of noble Romans, the pavements were in tessellate work or in marble sectile, and the walls decorated with marble or glass by subjects and pattern; here is the passage from Holland's quaint translation: "Scaurus when he was Edile caused a wonderfull piece of worke to be made, and exceeding all that had ever been knoune wrought by man's hand . . . and a theatre it was: the stage had three lofts one above another . . . the base or nethermost part of the stage was all of marble, the middle of glass, an excessive superfluitie never heard of before or after." Signor Luigi Visconti informed Herr von Minutoli (Ueber die Anfertigung und die neu-Anwendung der färbigen Gläser bei den Alten, p. 13 Berlin, 1836) that the walls of a chamber in a palace between the gate of St. Sebastian and that of St. Paul at Rome were found covered up to five or six feet from the pavement with beautiful marbles and above that with coloured glass plaques and patterns. Some existing examples appear to have been of curious structure, the pieces of coloured glass were laid upon a flat surface and a sheet of glass laid over these and melted to a sufficient heat to join them together.

Concerning the method called "tessellatum" we have existing remains to prove the perfection to which the art was carried by the Romans in the pavements, and in remains of wall glass mosaic at Pompeii. One of the finest examples of pavements is the representation of the "Battle of Issus" from the Casa del Fauno at Pompeii, now in the Naples Museum. Many of the pictures and mosaics in Pompeii are supposed to be traditional copies of celebrated antique paintings; and it is suggested that this "Battle" is a traditional copy of a celebrated picture by Helen, a daughter of Timon, of the Egyptian Hellenic school. From Pompeii came further the very beautiful columns in glass mosaic now in the Naples Museum. Pompeii, as we know, was destroyed on 24 August, A.D. 79, so that these works precede the Christian Era. Their perfection argues a development of considerable antiquity, the genesis of which is at present unknown. Of the subsidiary works in mosaic of Roman pavements, mention has already been made — it consists of patterns in black and white, plain floors with ornamental borders; groups of still life festoons of flowers, and other designs. These exist in sufficient quantity to show how general was their use. That mosaic pavements continued in use during the Christian era is proved by the numerous examples that have been discovered, apparently of Roman origin, at places as distant from one another as Carthage, Dalmatia, German, France, and England. In England a great variety have been found in London and in all parts of the country dominated by the Romans. The British Museum contains many mosaic fragments; amongst these is the fine specimen of work from Carthage. Some of the earlier Carthaginian pavements have glass tesserae; the later ones are of marble or ceramic cubes.

Entirely different in method from the work formed of cubes was the opus sectile, where, as already described. the ornament or picture was formed of pieces of marble, stone, or glass of different colours cut to a required shape, in the same way that a painted glass window is now made. The manufacture of the necessary opaque glass was carried to a very great perfection by the Romans, as is testified by the multitude of fragments that have been found in mounds of rubbish or in the Tiber. Opus sectile as a wall decoration seems to have been very subject to decay, the pieces of glass becoming detached by their own weight, on the wall becoming damp, decayed, or shaken. There are some very fine specimens in the Naples Museum; others have been found in the church of St. Andres in Catabarbara, Rome, which is supposed to have been originally the basilica of the house of the Bassi on the Esquiline dating from about A.D. 317. From this house comes the spirited work of the "Tiger and Heifer." now preserved in the church of St. Antonio Abbate. The background and stripes of the tiger are in green porphyry the rest of the tiger's skin of giallo antico; the heifer is pale fawn marble, and its eyes of mother-of-pearl. Other decorations of the same house showed that the walls had opus sectile in glass ornament and figures, much in the manner described in the quotation from Pliny, already given. Sectile work in glass is found in some examples of Christian art, but marble is more common, although the tessellated work in the same buildings may be of glass. This use of marble probably arose from the decay in the manufacture of the special glass and the difficulty of cutting and grinding it exactly to the forms. Sectile in marbles is found in Santa Sabina, Rome (425-450), in the baptistery of the cathedral, Ravenna; in San Vitale Ravenna (sixth century); at Parenzo (sixth century); in Sancta Sophia at Constantinople and at Thessalonica (sixth century); its use thus has been continuous ever since, and was an especial feature of the Renaissance.

The portion of this theme of the greatest importance in the present article is that concerned with the glass mosaic of Christian churches. The initial steps by which it gradually emerged from Pagan art are in a measure lost, for it rises suddenly like a phoenix from the ashes, complete, entire in its manipulation, whilst the character of the subjects and designs represented bespeak the traditions adopted by the artists of the catacombs. Mosaic, as far as one can at present ascertain, became a vehicle of Christian art in the fourth century. The earliest examples, such as those of the first basilica of St. Peter and St. Paul are all destroyed. In the church of St. Costanza on the Via Nomentana there still remains interesting work. We have also preserved in the Chigi Library some mosaic from the catacomb of Cyriacus. A mosaic of St. Agnes in the catacomb of St. Callistus was, however, so decayed, that the existing picture was painted over it in the sixth century. Other mosaics have been found on sarcophagi in the catacombs. The most interesting early works, however, that now existing in the apse of the church of St. Pudentiana (398). It has been much restored in parts and was added to in 1588, but the design remains. Of the same period is the mosaic in the baptistery at Naples. It is uncertain whether the apse of Sts. Rufinus's is of the fourth or fifth century, but it is interesting as early work.

A great impetus to the art occurred when Constantine, in establishing himself on the throne of Byzantium, commenced to give his capital an imperial appearance as far as art was concerned. He gathered together artists from all celebrated centres, and gave to them special legal and civil or civic favours. Of the works carried out by them, the mosaics of the church of St. George at Thessalonica in many cases yet occupy their original position. The nave of St. Mary Major's in Rome still retains some of the fine mosaics placed there in the fifth century (430-440) and the churches of St. Sabina (422- 433), of St. Paul without the walls, and of St. John Lateran were also so decorated in the same era (446-462). St. Paul's, destroyed by fire in 1823, has since been restored and little of the original remains. What remains of the original mosaics of St. John Lateran's dates from 432-440. The mosaics of the church of Saints Cosmas and Damian (532-530) were restored in 1660. At Ravenna the mosaic work in the various churches is the finest of its period. That in the baptistery of the cathedral dedicated to St. John the Baptist is an especially good example, the church being originally built at the end of the fourth century but burnt in 434. The mosaics of the Mausoleum of Galla Placidia (450) are also of excellent design and workmanship. Unfortunately some of these have been restored with painted stucco. Those in the chapel of the archiepiscopal palace and of the church of St. John the Evangelist are too of this period. The mosaics of the cathedrals of Novara and Aosta and the chapel of St. Satira in St. Ambrose's, Milan, are also of the fifth century. In France at Nantes, Clermont, and Toulouse historians record the placing of mosaics which no longer remain.

The greatest works of the sixth century, and perhaps the greatest of all mosaic works in extent, were those carried out under the Emperor Justinian in Sancta Sophia, Constantinople. In 533, a fire destroyed what then existed, but in a quarter of a century the restoration was commenced under Anthemios and Isidore, who, it is recorded, employed ten thousand builders, craftsmen, and artists. The colour is subdued, and the design and execution good of its period. Justinian also caused the church of Sancta Sophia at Thessalonica to be built, and decorated with mosaic. Further great works were executed at Ravenna at the same period. After the conquest by Belisarius in 539, it became the residence of the exarchs in 552, and S. Apollinare Nuovo, S. Maria in Cosmedin (553-566), S. Vitale (524-534), and S. Apollinare-in-Classe (534-549) were built and filled with mosaics. It will be observed that these churches were commenced under the Ostrogoths and finished under Justinian, who probably had the mosaics executed by local artists. The names of Euserius, Statius, Stephano, etc. are recorded. Greeks may have worked with them. The design of the work in S. Apollinare Nuovo is new to Western art and consists of two processions of figures very similar, which extend along the whole of the nave over the arches. It is curious that in the mosaics of the Adoration of the Magi the Magi wear the same Persian costume we find worn by Persians in the Pompeiian mosaic of the "Battle of Issus" which is not unlike that in the painting of the three children in the furnace in the catacomb of St. Priscilla, and that in the mosaic of the prophet Daniel at Daphne. The mosaic from S. Michele-in-affrisco at Ravenna was taken to Berlin in 1847 and Pope Adrian I permitted Charlemagne to take what he chose of marble and mosaic for his cathedral at Aachen. In Rome the church of Saints Cosmas and Damian (526-530) has mosaics of an entirely different character from those at Ravenna and of a ruder type. In Rome also the basilica of St. Lawrence was decorated with mosaic (577-590). These have been restored. In Paris the church of the Apostles which occupied the site where the Panthéon now is was decorated with mosaic about this period.

Notwithstanding the deplorable condition of Rome in the seventh century, the arts were still kept alive and Pope Honorius decorated the tribune of the apse of St. Agnes's with a beautifully designed mosaic which still remains. The composition represents in the centre St. Agnes, above her the Divine Hand blessing, and the popes Honorius and Symmachus on each side. The work appears to be Greek. In the chapel of St. Venantius at St. John Lateran's, and at St. Stephen's on the Coelian Hill some mosaics were placed by John IV; other works were done at St. Peter's and at St. Costanza's on the Via Nomentana. Mosaics were also executed for Autun and Auxerre in France. An immense and very fine pavement of this period was found by M. Renan in ancient Tyre, but it is not Christian art. Of the eighth century very little mosaic remains. Considerable work was done in the old basilica of St. Peter of which only a fragment, which came from one of the chapels, exists. It is in S. Maria in Cosmedin and represents part of the "Adoration of the Wise Men" and strikingly resembles the design of same subject in enamel on the "Chasse de Huy". The mosaic was commissioned by John VII in 705-8. In the apse of St. Theodore's, restored in the last quarter of the eighth century, there is a "majesty": Christ is seated on an orb with Sts. Peter, Paul, and Theodore. The triclinium of the Lateran Palace was ornamented with a mosaic of Christ appearing to the Apostles. On the sides were the groups of Christ and St. Sylvester, Constantine, Copronicus, and St. Peter with Leo III and Charlemagne — all these mosaics, never of high class, were injured by removal and restoration in the eighteenth century. The cathedral of Aachen executed from the orders of Charlemagne at this period was injured by fire in 1650, and utterly destroyed soon afterwards. Certain mosaics are known to have existed in Picardy and were eventually destroyed by fire in the twelfth century. Some good fragments of interesting mosaic of the early ninth century remain at Germingy-des-Prés, Loiret, France.

In the ninth century, although the decadence in mosaic work was complete, there was however an attempt at a slight revival. In Rome mosaics were placed in the churches of Sts. Nereus and Achilles (795-816), S. Maria (817-24), S. Prassede, S. Cecilia, St. Mark, Sts. Sylvester and Martin (844-847), and portions of St. Peter's and of S. Maria in Trastevere (885-888). Mosaic was placed in S. Margaretta in Venice (837), in St. Ambrose's Milan, and in Sancta Sophia at Constantinople, and some subjects were inserted in the cathedrals of Capua and Padua. Probably the most interesting of the period are those in S. Prassede, where that in the apse appears to be an adaptation of an older design in Saints Cosmas and Damian. In the tenth and eleventh centuries some mosaics were placed in St. Mark's Venice, one subject representing Christ, with the Blessed Virgin and St. John on each side, and in 1071-1084 the Doge Domenico Selvo had other mosaics executed, notably in the grand dome, and portions of the pavement. It is likely that the smalti were made by the Greeks, who were also probably the designers and executants.

A comparison of the western works of this period with those in the east is very unfavourable to the former. The art had been degenerating in the West, and in certain instances, such as that of Sancta Maria Antiqua, painting, on the wall had taken its place. Evidence of this decay, both in design and practice is shown in the fact that when Abbot Desiderius, formerly legate at Constantinople and who became pope as Victor III, wished to decorate the monastery of Monte Cassino with mosaics, he brought artists and workmen from Constantinople in 1066 for that purpose. These mosaics are lost or decayed, but it is not unlikely that the artists so engaged, designed and worked on the wall paintings of Sant' Angelo-in-formis, a subsidiary church of the monastery near Capua. These most interesting paintings are still in a fair state of preservation. It is probable that this action of Desiderius had a far- reaching influence in importing fresh energy especially when he came to occupy the papal chair. The schools of Paulus Laurentius and Rainerius were founded, which were ultimately influenced by the Cosmos, and all the work of this character was at one time erroneously called cosmati work. The generation of these schools is of considerable interest in the history of mosaic and is given by Mr. A. L. Frothingham, in the "American Journal of Archeology", I, 182. The main features of the decorative mosaic of the Roman School were derived from southern Italy, indirectly from Byzantium, in the eleventh century. The mosaics of the twelfth century are remarkable both for their number and the development of design in Christian art. A new period was inaugurated in Rome under Innocent II. In Italy, in Greece, in Arabia, as well as in Germany and France, important examples are preserved. In Rome, S. Maria in Trastevere (where the design and execution of the mosaic in the apse is extremely grand), S. Crisogono, S. Maria, and S. Francesca Romana were also so decorated.

The Roman artists exerted great influence in Umbria, and the Abruzzi, including the Marches. These men were at times both architects, mural painters, and mosaic workers. From the Roman centre their works went west to considerable distances. Other great works in Italy of this period are in the cathedral of Torcello, in the chapel of St. Zeno, and in the apse of St. Mark's at Venice, 1159; in the Palatine chapel, in S. Maria Martorana or S. Maria dell' Ammiraglio in Palermo, in other Sicilian churches both of Monreale and of Cefalù (1140) in the Palace chapel Arab workmen assisting the Greeks both in the design and execution. The Mohammedans themselves, notwithstanding the order of the prophet, had occasionally figure design in the mosaic of their mosques; that of Abd-el-Melik at Jerusalem has figures of prophets in the porch, and on the walls inside an Inferno and a Mohammedan Paradiso. The mosaic ornamentation in the mosques of Seville, Cordova, and Granada are well-known to travellers. In Greece there still remain most interesting mosaics of the churches of Daphne, and of St. Luke of Stiris in Phocis. In Syria, there remain the celebrated series of mosaics in the church of the Nativity, Bethlehem; those in the Church of the Holy Sepulchre, and the Mosque of Omar. The mosaics of this period in the churches of Mount Athos are all lost excepting a few figures at Vatopedi. In France, Abbot Suger had mosaics executed for the church of Saint Denis, and there are records of such work at Lyons and Troyes.

The great period of Christian mosaic was probably in the thirteenth century. Rome, Florence, Pisa, Venice, Parenzo, and Spoleto still possess great works of this era, and the names of Cimabue, Giotto, P. Cavallini, Gaddo Gaddi, Jacobus Torriti, Tafi, Apollonio, and others are connected with the craft. Torriti did important work in St. Mary Major's and St. John Lateran's; Pietro Cavallini designed the subjects under the apse of S. Maria in Trastevere; important mosaics were done in St. Peter's, St. Clement's, and other churches. In 1298 the great Giotto was called to Rome to design the "navicella" for the Porch of St. Peter's; that now in situ is a restoration. In Florence the mosaics of the baptistery commenced in 1225 by Jacobus, a Franciscan, were continued at the end of the century by Andrea Tafi, Gaddo Gaddi, Apollonio, and afterwards by Agnolo Gaddi. Gaddo Gaddi also did the beautiful "Madonna" at Santa Maria del Fiore, and the "majesty" at San Miniato is also attributed to him, but it is so much restored that it is difficult to pass judgement upon it. At the end of the century (1298-1301) there was executed the celebrated "majesty" in the apse of the cathedral at Pisa. This has generally been attributed to Cimabue and the side figures to Vicino. To this opinion Venturi adheres with strong evidence (Storia dell'Arte Italiana V, 239-240). Gerspach, however, will not have Cimabue amongst the mosaicists (La Mosaique, 127). At Cività Castelana there is a considerable work by the Cosmati, who possessed a school of architects, artists, and mosaicists. They not only did mosaic pictures or subjects, but enriched the altars, pulpits, columns, pavements, and other portions of the architecture with geometrical mosaic patterns.

The earliest Christian mosaics in England are of this century, when the beautiful pavement placed before the shrine of St. Thomas in Canterbury cathedral, and that of the sanctuary of Westminster Abbey was laid, and the shrine of St. Edward the Confessor with its inlaid mosaic, was executed. Concerning this last, Robert de Ware was sent by the king to Rome in 1267 to procure workmen for the ornamentation of Westminster Abbey and to erect a new monument to St. Edward the Confessor, that made in 1241 not being good enough. The abbot brought back with him one "Petrus", who laid the mosaic pavement before the high altar and executed the tomb for the golden shrine of St Edward. That this Petrus was an eminent person is without doubt. There are recorded many artists of this name, but he who, in the opinion of Mr. Frothingham (American Journal of Archeology, 1889, 186), did the work in St. Edward's Chapel was Petrus Orderisi, son of Andreas. Horace Walpole (History of Painting in England, I, 17) considers that the artist so called was Pietro Cavallini; both these artists may be termed Cosmateschi. A portion of the inscription reads: HOC OPUS EST FACTUM QUOD PETRUS DUXIT IN ACTUM ROMANUS CIVIS.

The work of the fourteenth century in Rome and in Italy generally was a continuation of that of the thirteenth, the design towards the end of the era becoming influenced by the rising art of the more western styles. In St. Mary Major's the "Coronation of The Blessed Virgin" was commenced at the conclusion of the thirteenth and completed early in the fourteenth century it is signed by the celebrated artist and mosaicist Jacobus Torriti. Gaddo Gaddi designed the smaller subjects underneath, soon afterwards. The same artist is said to have completed the work in St. Peter's left by Torriti. He was then called to Arezzo to do the vault of the cathedral, which fell away before the end of the century. Torriti also did the apse of St. John Lateran's; Filippo Rusuti designed the "majesty", and Gaddo Gaddi the lower subject of the façade of St . Mary Major's, Rome. A mosaic by Munio de Zamaro, a Dominican who died in 1300, is on the floor of St. Sabina's. At the beginning of the century the work in St. Mark's, Venice, was continued. A mosaicist, Solferino, did the dome at Spoleto; and the apse at Parenzo was filled with mosaic. Perhaps the most important developments of the art are shown in the subjects decorating the lower part of the apse of S. Maria in Trastevere; in 1291 these subjects were commenced by Pietro Cavallini, who is said by Vasari to have been a pupil of Giotto, although this is questioned by modern critics on fairly substantial evidence. He was the most celebrated Roman artist of his time and his designs, while adhering more to the Byzantine than those of Giotto did, show a tendency that may be called Gothic development. His accessories show his cosmatesque affinity. This is very noticeable in the throne of the Blessed Virgin in S. Crisogono.

Mosaic work of the period remains at Salerno, Naples, and Ravello; at Feranio there are mosaics by Deodato Cosmos (1332); at Orvieto by two religious Ceco Vanni and Francesco; at Pisa (in 1321) by Vicino, who finished that commenced by Cimabue from the designs of Gaddo Gaddi. Andrea di Nino and Michele worked in the cathedral of Sienna, and Deodato Cosmos worked at Teramo. Charles IV called Italian mosaicists to Prague; they also worked at Marienweide and Marienburg, but the art did not apparently thrive in Germany. Mosaic was, however, being rapidly superseded by fresco, which as a primary art giving the sentiment and character of the artists immediately, was of course much more esteemed by persons of discrimination than a mere copy in tesserae, or slabs of opaque glass. Hence in the fifteenth century the cessation of mosaic work in Italy generally was very notable, except in the case of churches in which it had been commenced. Some little was done in St. Peter's, and the work in St. Mark's, Venice, was continued in 1430, when in the chapel of the Mascoli the "Life of the Blessed Virgin" was designed and executed by Crambono. Mosaicists named Petrus, Lazarus, Sylvester, and Antonius also worked there. In Florence, Alessandro Baldovinetti (1425-1450) did a mosaic for St. John's and restored that in San Miniato; he studied the making of smalti, etc. from a German and wrote a work on the technique of the art. He was the master of Domenico Ghirlandajo, who not only did the mosaic of the "Assumption" over a porch of the cathedral and those unfinished in the chapel of St. Zenobius, but also designed some of the painted windows in S. Maria Nuova, and whose brother David also followed the same vocation and in 1497, worked at Orvieto and Siena. A specimen of David's work is in the Musée de Cluny. Ridolfo Ghirlandajo, son of Domenico and a friend of Raphael, has certain later mosaics attributed to him.

In the sixteenth century the work of St. Mark's was still carried on and a great many artists of reputation were engaged on the designs. The mosaics executed in this cathedral commencing in 1530, are far too numerous to recapitulate here, and are perhaps less fitted to the building than any hitherto placed; in fact, that greatest of painters, Titian when rendered in mosaic, becomes coarse, heavy, and, on occasions grotesque. Other works were designed by Tintoretto, Salviati, and the best Venetian artists of the day and rendered in mosaic by Zuccati, Rizo, Mariano and others. Unfortunately many of the earlier mosaics were destroyed by the senate, it is said, on the advice of Titian, to make room for the new work. The condition of many of them was bad. Amongst his many other works, Raphael designed for mosaic. The "Creation of the World" in the Chigi Chapel Santa Maria del Popolo, Rome, from his design, is very fine. It was done in mosaic by Luigi di Pace, who came from Venice for the purpose. Baldasare Peruzzi also designed mosaic for Santa Croce in Gerusalemme, and F. Zucchio executed a mosaic in Santa Maria Scala-Caeli, whilst the work in St. Peter's was commenced under Muziano da Brescia. That the mosaic art had degenerated altogether and lost its vitality is evidenced by the work done in St. Peter's, Rome, from the seventeenth century under this same Muziano da Brescia (1528-1592) and other artists.

The establishment of the pontifical works commenced in 1727 when the Cristoferi were appointed superintendents by order of Benedict XIII. After occupying various localities these mosaic works were finally settled in a cortile of the Vatican in 1825. In the first half of the seventeenth century the painting and frescoes of the basilica began to be imitated in mosaic. The quality of the work errs on the side of excessive smoothness, as much as some modern workers on that of excessive and affected roughness. Other work of the eighteenth and nineteenth centuries and great restorations kept the art alive, notably those of St. John Lateran's and St. Mark's, Venice, by the Italian mosaicists. The "Last Judgments" on the façade of St. Mark's designed by Latanzio Querano in 1836. In 1839 a school of mosaicists arose in Russia, its primary object being the restoration of the mosaics of Sancta Sophia in Kieff, and eventually Pius IX allowed certain of the pontifical mosaicists in 1850 to go to St. Petersburg and join the Russian mosaicists. An example of their work was shown in the international exhibition held in Hyde Park London. The mosaics of the Russian church, London, are not, however, very successful.

Numerous mosaics have been executed in England during the last half century notably the figures of great painters in the Museum of South-Kensington. The earliest of these were done by Venetians, but some of the more recent figures were executed at the works of South- Kensington itself. Many mosaics were done in St. Paul's cathedral, London; those in the choir were designed by Sir W. B. Richmond and under the dome some strong figures were designed by Mr. Watts, R.A. The mausoleum at Frogmore is also elaborately decorated with mosaic, as is the monument of Prince Albert in Hyde Park, both designed by John Clayton, who is also responsible for the Brampton chapel in Westminster cathedral. Mr. W. C. Symons designed the mosaics for the chapel of the Holy Souls of Westminster cathedral in which mosaic work is still being inserted in the various chapels. The writer of the present article designed a mosaic of the "Last Judgment" for the church of the Annunciation, Chiselhurst; a figure of Blessed Giacomo di Ulma for South-Kensington, and an "Epiphany" for the frontal of an altar at the Assumption Church Warwick Street, with other works elsewhere.

In Aachen the mosaic of the dome of Charlemagne was restored, or rather redone, in 1869. In France various mosaics of fair excellence have been executed but unfortunately the grand style of the early centuries so exceptionally suitable to the art, has not been attempted. The modern French mosaic appears to have been initiated by Signor Bellini, one of the Vatican mosaicists, at the close of the eighteenth century who became the principal of the "manufacture royale" — one of its productions is in the Salle de Melpomène in the Louvre; the design was by Baron Gérard and M. Baudry Garnier, and the mosaic by Curzon Facchino. The mosaics at the Opera are of Italian execution. In 1876 a national school of mosaic was formed. When M. Gerspach was sent to Rome and obtained, with the consent of the pope, the services of Signor Poggesi of the Vatican works. The execution of the apse of the Panthéon from designs of M. Herbert was the principal work that followed, but the design is moderate. although considered good in its time. This national school soon became extinct, and the mosaics since done have been by private enterprise. Amongst these is that in the apse of the Madeleine and that over the grand staircase of the Louvre. M. Ravoli has designed some mosaics for the new cathedral of Marseilles.

Technique

The making of a mosaic picture has differed in various periods and under various manufacturers, and the cements into which the tesserae were fixed have been the subject of discussion and in some medieval examples, of secrecy. Historically no cement has effected a permanent mosaic, as nearly every ancient example not destroyed is partially restored. The following interesting account is from the personal examination by Messrs. Schultz and Barnsley of the old work at St. Luke's of Stiris:

"The method of fixing the mosaic was as follows: — over the structural brick work of the surfaces to be covered, a coat of plaster was spread; this, like the first coat of plaster in ordinary wall coverings was roughened on the face in order to make a second coat of finer stuff adhere. On the surface of this second coat, which was evidently of a very slow-setting nature, the main lines of the mosaic figure or composition were sketched on in tone with a brush and the mosaic cubes were then pressed into this from the face, forcing up the stuff between the cubes in order to act as a key. We are inclined to think that at any rate in the case of the single figures, the first cubes put in position were the double or treble row of gold tesserae which enclosed the subject; we have found in many cases that these do not correspond with the lines of the figures was executed, odd spaces between the lines and the final outline of the figure having been filled up with further gold cubes after the mosaics of the figure have been finished in position. The backgrounds are universally formed of gold tesserae, while the figures of subjects are composed of cubes of many colours and gradations of tone. The principle coloured cubes are cut out of sheets of opaque coloured glass, while the lighter ones, such as the flesh tints, etc., are of marble. The gold mosaics are formed in the usual manner; a piece of gold leaf, having been laid on glass, a thin transparent film was then spread over the same, and the whole afterwards annealed to a solid mass. The cubes do not vary greatly in size, the average being about three-eighths of an inch. They are, however, slightly larger in the main outlines of the draperies, etc., and smaller in the delicate gradations of the face and hands The main portion of the gold background laid fairly regularly in horizontal lines up the rows enclosing the subjects" (Schultz and Barnsley, "The Monastery of St Luke in Stiris", 43).

Bibliography Information
Obstat, Nihil. Lafort, Remy, Censor. Entry for 'Mosaics'. The Catholic Encyclopedia. https://www.studylight.org/encyclopedias/eng/tce/m/mosaics.html. Robert Appleton Company. New York. 1914.

Bible Encyclopedias Mosaics

The Catholic Encyclopedia

Bible Encyclopedias
Mosaics