[3] Donatus was born in Euroea, Epirus Vetus (northwestern Greece) and lived during the reign of the Emperor Theodosius I.

According to the 5th-century historian Sozomen, Saint Donatus was Bishop of Euroea, identifiable with Glyki in Epirus, Greece.

[5] The saint is said to have accomplished several miracles, such as successfully fighting a dragon, purifying well waters, saving the emperors' daughter, and reviving the dead.

However this led to a problem of jurisdiction and custody for the holy relics, which was resolved by Pope Gregory I. Donatus's cult was widespread in the Middle Ages.

Umbriatico Cathedral in Calabria in the south of Italy is dedicated to him: the area was occupied by Epirote troops after the conquest of Nikephoros Phokas the Elder in the 9th century, who brought with them the cults of the saints familiar to them.