Giovanni Pisano had any share in the sculpture on the facade of
the cathedral at Orvieto, is not known for certain. Vasari asserts that
Niccola and his pupils worked upon this series of bas-reliefs, setting
forth the whole Biblical history and the cycle of Christian beliefs from
the creation of the world to the last judgment. Yet we know that Niccola
himself died at least twelve years before the foundation of the church in
1290; nor is there any proof that his immediate scholars were engaged upon
the fabric. The Orvietan archives are singularly silent with regard to a
monument of so large extent and vast importance, which must have taxed to
the uttermost the resources of the ablest stone-carvers in Italy.[66]
Meanwhile, what Vasari says is valuable only as a witness to the fame of
Niccola Pisano. His manner, as continued and developed by his school, is
unmistakable at Orvieto: but in the absence of direct information, we are
left to conjecture the conditions under which this, the closing if not the
crowning achievement of thirteenth-century sculpture, was produced.

When the great founder of Italian art visited Siena in 1266 for the
completion of his pulpit in the Duomo, he found a guild of sculptors, or
_taglia-pietri_, in that city, numbering some sixty members, and governed
by a rector and three chamberlains. Instead of regarding Niccola with
jealousy, these craftsmen only sought to learn his method. Accordingly it
seems that a new impulse was given to sculpture in Siena; and famous
workmen arose who combined this art with that of building. The chief of
these was Lorenzo Maitani, who died in 1330, having designed and carried
to completion the Duomo of Orvieto during his lifetime.[67] While engaged
in this great undertaking, Maitani directed a body of architects,
stone-carvers, bronze-founders, mosaists, and painters, gathered together
into a guild from the chief cities of Tuscany. It cannot be proved that
any of the Pisani, properly so called, were among their number. Lacking
evidence to the contrary, we must give to Maitani, the master-spirit of
the company, full credit for the sculpture carried out in obedience to his
general plan. As the church of S. Francis at Assisi formed an epoch in the
history of painting, by concentrating the genius of Giotto on a series of
masterpieces, so the Duomo of Orvieto, by giving free scope to the school
of Pisa, marked a point in the history of sculpture. It would be difficult
to fi