Florence - Baptistry of St John Battistero San Giovanni

Ghiberti adopted an entirely new approach when he came to design his greatest work, the east portal. Michelangelo considered it worthy to serve as the Gate of Paradise - hence "Porta del Paradiso" - and Ghiberti himself sang its praises by adding "mira arte fabricatum" (made with admirable art) on the right-hand door next to his signature. In 1990 the original door was replaced by a replica and can now be admired in the Museo dell'Opera del Duomo.

Nowhere else has a sculptor expressed himself in bronze as perfectly as in this door, created between 1425 and 1452. The ten separate panels contain reliefs of scriptural subjects. The framing incorporates figures of prophets and sibyls and portrait medallions, including one of Ghiberti himself (fourth from the top in the middle row on the left). The beauty and mastery of the finely delineated perspectives, the three-dimensional levels of representation, the individual characterisation of the figures, the meaningful composition of the groupings, all combine in the consummate perfection of the whole.

From top left to bottom right the panels depict:

Adam and Eve: creation, fall, expulsion from Paradise;

Cain and Abel: sacrifice by Cain and Abel, death of Abel, punishment of Cain;

Noah: his sacrifice, departure from the Ark, his drunkenness;

Abraham and Isaac: angel appearing to Abraham, Isaac's sacrifice;

Jacob and Esau: birth of Esau and Jacob, selling the birthright, Esau hunting, Rebecca, Isaac's betrayal;

Joseph: selling of Joseph, Benjamin, Joseph and his brothers;

Moses: Moses receiving the Tablets of the Law on Mount Sinai;

Joshua: the Jews before Jericho, encampment, the walls come tumbling down when the trumpets sound;

Saul and David: battle with the Philistines, slaying of Goliath;

Solomon and the Queen of Sheba.

This door rightly has the place of honor opposite the Duomo Santa Maria del Fiore.

The sombre, mystical nature of the dim interior of the Baptistry comes as something of a surprise after the clearcut articulation of the exterior. It is dominated by the octagonal dome (diameter 25.6m/84ft) which is completely lined with mosaics, the work of Florentine artists (Jacopo da Torrita, Cimabue, Andrea di Riccio, Gaddo Gaddi) in the 13th century or possibly about 1300 and therefore at the time of Dante. One of the greatest mosaics in the Western world, it is as outstanding for its treatment of its subject matter as for the richness of its ornamentation.

Above the choir chapel is the gigantic figure of Christ - the face alone measures 8m/26ft - as Judge of the World at the Last Judgment. Grouped around him, in different sections, are the figures of the Resurrected and the Damned, of angels, apostles, prophets and saints, with Mary and John the Baptist ranged against the realm of the Devil, devourer of men. (It is worth remembering that Dante, Italy's greatest poet, who described Heaven, Purgatory and Hell in his "Divine Comedy", hailed from Florence.) Other vivid mosaics depict the Creation, scenes from the life of Joseph and the lives of Jesus Christ, Mary and John the Baptist.

Also of interest are one of Donatello's masterpieces, the tomb of the Antipope John XXIII (deposed by the Council of Constance), and the niello decoration of the marble floor (zodiac and metallic ornamentation), the marble font, the sarcophagus of Bishop Ranieri and the high altar with a candlestick in the form of an angel.

Another of Donatello's masterpieces used to stand in the Baptisty - his wooden statue of Mary Magdalene - but this is now in the Museo dell'Opera del Duomo.

In 1401 Lorenzo Ghiberti beat six others (including Brunelleschi and Jacopo della Quercia) to win the competition for the north portal. From 1403 to 1424 Ghiberti worked on the bronze doors with his assistants (Masolino, Donatello, Paolo Uccello, Bernardo Ciuffagni, Bernardo Cennini) and in doing so adhered closely to Andrea Pisano's design for the south portal: 28 square panels each with a Gothic relief, twenty of them scenes of the Life of Christ and eight of them the figures of the four Evangelists and four Early Fathers of the Latin Church. His work, however, far excels that of Pisano in the grace of the figures and the liveliness of expression.

Ghiberti's difference of approach, while still keeping to the traditional forms, is particularly evident in the vivid scenes of the "Resurrection" (right-hand door, top row, left), the "Baptism" and the "Temptation of Jesus" (left-hand door, fourth row down, left and right), the "Nativity" (left-hand door, fifth row down, right) and "Christ among the Doctors" (right-hand door, fifth row down, right).

Ghiberti also designed the bronze framing of the portal from which small heads protrude at every intersection.

The south portal is the oldest and was designed by Andrea Pisano (1318-1330) and cast by Leonardo d'Avanzano (1330-1338). It is divided into 28 square Gothic panels. With workmanship reminiscent of the art of the goldsmith, the reliefs on 20 of the panels depict scenes from the life of John the Baptist, partron saint of the church; the other eight panels are allegorical representations of the theological and cardinal virtues. Every figure stands out in clear relief, each one a unique work of art in the modelling of the face, of the folds of the garments and the expressive posture of the body.

The decorations of the framing are by Vittorio Ghiberti, son of Lorenzo, and their foliage, creatures and fruit are an early indication of the wealth of form that characterized the Renaissance.