ey have lain for some time, and throw
out shoots which afterwards produce greater and better fruits than the
first plants had done. Agostino and Agnolo, then, adding great
betterment to the manner of Giovanni and Niccola of Pisa, enriched the
art with better design and invention, as their works clearly
demonstrate. It is said that the aforesaid Giovanni, returning from
Naples to Pisa in the year 1284, stayed in Siena in order to make the
design and foundation for the facade of the Duomo, wherein are the three
principal doors, to the end that it might be all adorned very richly
with marbles; and that then Agostino, being no more than fifteen years
of age, went to be with him in order to apply himself to sculpture,
whereof he had learnt the first principles, being no less inclined to
this art than to the matters of architecture. And so, under the teaching
of Giovanni, by means of continual study he surpassed all his
fellow-disciples in design, grace, and manner, so greatly that it was
said by all that he was the right eye of his master. And because,
between people who love each other, there is no gift, whether of
nature, or of soul, or of fortune, that is mutually desired so much as
excellence, which alone makes men great and noble, and what is more,
most happy both in this life and in the other, therefore Agostino,
seizing this occasion of assistance from Giovanni, drew his brother
Agnolo into the same pursuit. Nor was it a great labour for him to do
this, seeing that the intercourse of Agnolo with Agostino and with the
other sculptors had already, as he saw the honour and profit that they
were drawing from such an art, fired his mind with extreme eagerness and
desire to apply himself to sculpture; nay, before Agostino had given a
thought to this, Agnolo had wrought certain works in secret.

Agostino, then, being engaged in working with Giovanni on the marble
panel of the high-altar in the Vescovado of Arezzo, whereof there has
been mention above, contrived to bring there the said Agnolo, his
brother, who acquitted himself in this work in such a manner that when
it was finished he was found to have equalled Agostino in the excellence
of his art. Which circumstance, becoming known to Giovanni, was the
reason that after this work he made use of both one and the other in
many other works of his that he wrought in Pistola, in Pisa, and in
other places. And seeing that he applied himself not only to sculpture
but to architect