In the middle of the whole, in the centre at the lower corners of the Jacob and Joseph respectively, are portrait busts of Lorenzo Ghiberti himself and Bartolo di Michele. Vasari has said the last word:-- "And in very truth can it be said that this work hath its perfection in all things, and that it is the most beautiful work of the world, or that ever was seen amongst ancients or moderns. And verily ought Lorenzo to be truly praised, seeing that one day Michelangelo Buonarroti, when he stopped to look at this work, being asked what he thought of it and if these gates were beautiful, replied: 'They are so beautiful that they would do well for the Gates of Paradise.' Praise verily proper, and spoken by one who could judge them." The Baptism of Christ over the portal is an unattractive work by Andrea Sansovino (circa 1505), finished by Vincenzo Danti. The Angel is a seventeenth century addition. More interesting far, are the scorched porphyry columns on either side of the gate; these were part of the booty carried off by the Pisan galleys from Majorca in 1117, and presented to the Florentines in gratitude for their having guarded Pisa during the absence of the troops. Villani says that the Pisans offered their allies the choice between these porphyry columns and some metal gates, and that, on their choosing the columns, they sent them to Florence covered with scarlet, but that some said that they scorched them first for envy. It was between these columns that Cavalcanti was lingering and musing when the gay cavalcade of Betto Brunelleschi and his friends, in Boccaccio's novel, swooped down upon him through the Piazza di Santa Reparata: "Thou, Guido, wilt none of our fellowship; but lo now! when thou shalt have found that there is no God, what wilt thou have done?" From the gate which might have stood at the doors of Paradise, or at least have guarded that sacred threshold by which Virgil and Dante entered Purgatory, we cross to the tower which might fittingly have sounded tierce and nones to the valley of the Princes. This "Shepherd's Tower," according to Ruskin, is "the model and mirror of perfect architecture." The characteristics of Power and Beauty, he writes in the _Seven Lamps of Architecture_, "occur more or less in different buildings, some in one and some in another. But all together, and all in their highest possible relative degrees, they exist, as far as I know, only in one building in the world, the Campanile of Giotto."