Andrea Pisano was Nicola's greatest scholar, though not his son. He took the name of his master after the mediaeval custom. His work was largely in bronze, and the earlier gates of the Baptistery in Florence are by him. We have already alluded to the later gates by Ghiberti, when speaking of bronze. Andrea had the honour to teach the celebrated Orcagna,--more painter than sculptor,--whose most noted work in this line was the Tabernacle at Or San Michele. Among the loveliest of the figures sculptured by the Pisani are the angels standing in a group, blowing trumpets, on the pulpit at Pistoja, the work of Giovanni. Among Nicola's pupils were his son Giovanni, Donatello, Arnolfo di Cambio, and Lorenzo Maitani, who executed the delightful sculptures on the facade of the Cathedral of Orvieto,--perhaps the most interesting set of bas-reliefs in detail of the Early Renaissance, although in general symmetrical "bossiness" of effect, so much approved by Ruskin, they are very uneven. In this respect they come rather under the head of realistic than of decorative art. Lorenzo Maitani was a genuine leader of his guild of craftsmen, and superintended the large body of architects who worked at Orvieto, stone masons, mosaicists, bronze founders, painters, and minor workmen. He lived until 1330, and practically devoted his life to Orvieto. It is uncertain whether any of the Pisani were employed in any capacity, although for a time it was popularly supposed that the four piers on the facade were their work. An iconographic description of these sculptures would occupy too much time here, but one or two features of special interest should be noted: the little portrait relief of the master Maitani himself occurs on the fourth pier, among the Elect in heaven, wearing his workman's cap and carrying his architect's square. Only his head and shoulders can be seen at the extreme left of the second tier of sculptures. In accordance with an early tradition, that Virgil was in some wise a prophet, and that he had foretold the coming of Christ, he is here introduced, on the second pier, near the base, crowned with laurel. The incident of the cutting off of the servant's ear, by Peter, is positively entertaining. Peter is sawing away industriously at the offending member; a fisherman ought to understand a more deft use of the knife! In the scenes of the Creation, depicted on the first pier, Maitani has proved himself a real nature lover in the tender way he has demonstrated the joy of the birds at finding the use of their wings.