Between 1287 and 1296 he was appointed chief architect of Siena Cathedral.

He substantially changed the design and construction of the building, increasing the similarity of the building to Siena Cathedral.

The dome of Siena Cathedral had an exposed profile as early as 1224.

Originally, he would have emerged from the city's cisterns at Siena Cathedral, but this was thought disrespectful.

In 1265 he was already at work on the pulpit for the Siena Cathedral.

In September 1265 he was given his next major assignment : a marble pulpit for the Siena Cathedral.

In this period some cathedrals were also constructed or finished, such as Siena Cathedral.

During the early 13th century that the majority of the construction of the Siena Cathedral (Duomo) was completed.

In 1482, he worked on frescoes for the cupola in the Siena Cathedral.

It appears on the baptistry of the Siena Cathedral in Italy.