He reached his peak as a craftsman from about 1690 and his violins based on Amati's Grand Pattern are generally considered his best. By 1690 he was aided by his son Pietro Giacomo, who was a skilled assistant, and no doubt helped with the production of some lesser instruments, which often have unpurfled backs.
He reached his zenith as a craftsman from around 1690, and his violins based on Amati's Grand Pattern are typically regarded as his finest. By 1690 he was assisted by his son Pietro Giacomo, who was an accomplished helper, and likely contributed to the creation of some inferior instruments, which often have unfaced backs.