sentences:  One attractive theory is that they relate to an annual passion play, in which these notable figures may have played some part.In the more prestigious artistic centre of Florence the Della Robbia family became famous for their distinctive blue and white tin-glazed terracotta work, which was highly skillfully made yet provided relatively cheap decoration.Most closely related to the work of Mazzoni, however, is that of Niccolò dell'Arca, who operated in Bologna.