St. Donatus
 "At Arezzo in Tuscany the death of the holy bishop Donatus. Besides other miracles, he restored, by means of his prayer, a chalice broken by pagans, according to the account of Pope St. Gregory I. He was slain under Julian the Apostate about the year 363" (Martyrology).

Legend says that he was born at Nicomedia of parents who had both been slain for Christ's sake. With the holy monk Hilarinus he fled to Arezzo in Tuscany, of which city he afterwards became Bishop. There the Prefect Quadratian, during the persecution under Julian, about 362, commanded both Hilarinus and Donatus to worship idols, and when they both refused, they were slain. Hilarinus was beaten to death with clubs. Donatus was in diverse ways savagely tortured, and then put to the sword. The Christians buried their bodies honourably close by the city.

http://www.catholicculture.org/culture/liturgicalyear/calendar/day.cfm?date=2014-08-07