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.
From approximately 1690, he achieved his peak as a craftsman. His violins based on Amati's Grand Pattern are considered among his best works. By that time, his son Pietro Giacomo, who was skilled, helped with the production of some less refined instruments, which often had unfaced backs.