Miracles of the Synaxarion
According to the synaxarion, when Donatus learned of a brackish spring in the vicinity of Soreia near his city, he went to it with his clergy and cast out a monstrous serpent that infested the place; the serpent died, and the saint then prayed, blessed the spring, and drank its water without harm. On another occasion he brought forth water from a dry and rocky place by his prayer, and during a drought he entreated the Lord to send rain upon the parched land.
The tradition further relates that when the daughter of the Emperor Theodosius fell gravely ill and was afflicted by an unclean spirit, Donatus came to the imperial palace; as soon as he arrived the spirit departed and the woman was made well. He is also said to have raised a dead man so that his testimony might resolve a dispute with a creditor. Such accounts gave Donatus his standing as a wonderworker over both the natural elements and the powers of darkness.