The Christ of Piero Tedesco on the facade of the Cathedral had glass eyes.  Roland and Oliver, two wonderful creations on the facade of the Cathedral at Verona, had blue enamel eyes.  The Apostles in the Church of San Zeno, in the same city, are exceptionally interesting, being one of the rare cases where the genuine colouring is visible, although it has been much worn.  The early colourists used tempera;[163] as this perished, oil paint was substituted, and there are very few painted statues extant on which restoration has never taken place, and consequently where the original colour of the sculptor is intact.  With repainting, the original artist disappears:  even if the work is cast, the delicate tints of the first colouring must be impaired, and repainting follows.  Thus the Niccolo da Uzzano is covered with inferior oil colour, and only in a few details can the primitive tempera be detected.  The later addition creates the fictitious interest, and immensely reduces the real importance of this masterly production.

[Footnote 160:  Cf. Naples Museum, No. 5592.]

[Footnote 161:  Cf. drawings of facades in Vettorio Ghiberti’s Note-book.]

[Footnote 162:  Bargello Cortile, No. 3, by Niccolo di Piero.]

[Footnote 163:  Borghini, in 1586, gave a curious recipe for colouring marble according to antique rules.  Florentine ed. 1730, p. 123.]

* * * * *

[Sidenote:  Portrait-busts.]

It is a singular fact admitting of no ready explanation that portrait-busts, so common in Tuscany, should scarcely have existed in Venice.  Florence was their native home.  From the time of Donatello every sculptor of note was responsible for one or more, while certain artists made it a regular occupation.  Luca della Robbia, however, one of the most consummate sculptors of his day, made no portrait except the effigy of Bishop Federighi.  There are one or two small heads in the Bargello, but they scarcely come within the category of studied portraits, while the heads on the bronze doors of the Duomo, though modelled from living people, are small and purely decorative in purpose.  Glazed terra-cotta was a material so admirably adapted to showing the refinements of feature and character, as we can see in both Luca’s and Andrea’s work, that this absence is all the more surprising.  At the same time, numerous as portrait-statues were in Tuscany, they do not compare in numbers with those executed in classical times.  In the fifteenth century the statue was a work of art, and its actual carving was an integral part of the art:  so the replica in sculpture was rare.  But under the Roman Empire statues of the same man were erected in scores and hundreds in the same city; their multiplication became a profession in itself, and a large class of artisans must have grown up, eternally copying and recopying portrait-busts and giving them the haunting dulness of mechanical reproductions.