Italian sculptor, active in Siena. He was one of the sculptors, including Lorenzo Ghiberti, Donatello and Jacopo della Quercia, who worked in the BaptisteryGLOSSARYHall or chapel situated close to, or connected with, a church, in which the sacrament of baptism is administered. The form of the baptistery originally evolved from small, circular Roman buildings that were designated for religious purposes (e.g., the Temple of Venus, Baalbek, Lebanon, AD 273, and the Mausoleum of Diocletian, Spalato [Split, Croatia], AD 300); but because baptism originally was performed on only three holidays, Easter, Pentecost, and Epiphany, enlargement of the older Roman buildings became necessary to accommodate the growing numbers of converts. Baptisteries were among the most symbolic of all Christian architectural forms; and the characteristic design that was developed by the 4th century AD can be seen today in what is probably the earliest extant example, the baptistery of the Lateran palace in Rome, built by Sixtus III, pope between 432 and 440. The baptistery was commonly octagonal in plan, a visual metaphor for the number eight, which symbolized in Christian numerology a new beginning. As eight follows the "complete" number, seven, so the beginning of the Christian life follows baptism. Customarily, a baptistery was roofed with a dome, the symbol of the heavenly realm toward which the Christian progresses after the first step of baptism. The baptismal font was usually octagonal, set beneath a domical ciborium, or canopy, and encircled by columns and an ambulatory--features that were first used in the baptistery by the Byzantines when they altered Roman structures. Baptisteries commonly adjoined the atrium, or forecourt, of the church and were often large and richly decorated, such as those at Pisa, Florence, Parma, and Nocera in Italy; el Kantara, Alg.; and Poitiers, France. After the 6th century they were gradually reduced to the status of small chapels inside churches. In the 10th century, when baptism by affusion (pouring liquid over the head) became standard practice in the church, baptisteries, or baptismal chapels, were often omitted entirely. In most modern churches the font alone serves for baptism; something of earlier symbolism survives, however, in its usual location near the church door - an allusion to entering the Christian life. of Siena between 1417 and 1431 on the baptismal font made of marbleGLOSSARYloosely applied to any hard limestone that can be sawn into thin slabs and will take a good polish so that it is suitable for decorative work; more strictly, it refers to metamorphosed limestones whose structure has been recrystallized by heat or pressure. Marbles are widely disseminated and occur in a great variety of colours and patterns, but certain types have been particularly prized by sculptors. The most famous of Greek white marbles in the ancient world was the close-grained Pentelic, which was quarried at Mount Pentelicon in Attica. The Elgin Marbles are carved in Pentelic. Widely used also were the somewhat coarser-grained translucent white marbles from the Aegean islands of Paros and Naxos. Parian marble was used for the celebrated Mausoleum at Halicarnassus. The pure white Carrara marble, quarried at Massa, Carrara, and Pietra Santa in Tuscany from the 3rd century BC, is the most famous of all sculptors' stones. It was used for the Apollo Belvedere, and was much favoured in the Renaissance, particularly by Michelangelo, who often visited the quarries to select material for his work. Neoclassical sculptors also favoured Carrara marble because of its ability to take a smooth, sleek surface, but it can look rather 'dead' compared with some of the finest Greek marbles., bronzeGLOSSARYAn alloy of copper (usually about 90 per cent) and tin, often also containing small amounts of other metals such as lead or zinc. Since antiquity it has been the metal most commonly used in cast sculpture because of its strength, durability, and the fact that it is easily workable - both hot and cold - by a variety of processes. It is easier to cast than copper because it has a lower melting-point, and its great tensile strength makes possible the protrusion of unsupported parts - an advantage over marble sculpture. The colour of bronze is affected by the proportion of tin or other metals present, varying from silverish to a rich, coppery red, and its surface beauty can be enhanced when it acquires a patina., and enamelGLOSSARYColoured glass in powder form and sometimes bound with oil, which is bonded to a metal surface or plaque by firing..
