 He entered into the Dominican order in Florence in 1383, and after acting as a lettore for many years in various convents, including those of the Roman and Lombard provinces, he was made bishop of Acaia in 1413 by Pope John XXII.It is thought to be shortly after this time, around 1420, that he wrote a new vita in deference to his native city and to his particular devotion to Verdiana.His account borrowed faithfully from Biagio, though Giacomini sought to enrich it with miracles and information on the cult and translations of Verdiana known from contemporary traditions and his own experience.