DONATUS. - He was not the initiator but the head and principal instigator of the African schism that took its name from him (v. DONATISMO).
The distinction between a D. (the name was extremely common in Africa) of Casae Nigrae (Casinensis, Casensis) and one "of Carthage," both Donatist bishops, is not found in the sources before the conference of Carthage of 411. St. Augustine, not without some hesitation, accepted it (Retract., I, 20 or 21,3), and from then on it became traditional. But the circumstances in which it was proposed, and the fact that the one disappears precisely when the other enters the scene, have led various moderns to doubt this distinction and to reject it, following in the footsteps of Chapman; Casae Nigrae, in Numidia, could be the birthplace of D.
Of him it is further known that he wrote an epistle, in which he maintained that his party was the only one to possess a valid Baptism; it was refuted by St. Augustine in a work, Contra epistulam Donati haeretic, which is lost. He also wrote a treatise De Spiritu Sancto which St. Jerome (De vir. ill., 93) and St. Augustine (De haer., 69; cf. Epist. 185 or De corrept. Donatist., 1, 1) consider Arianizing, or at any rate not precisely orthodox with regard to the Trinitarian dogma: D. is said to have affirmed "that the Son is less than the Father, and the Holy Spirit less than the Son" ("quamvis eiusdem substantiae, minorem tamen Patre Filium et minorem Filio putasse Spiritum Sanctum").
It is quite probable that D. made some concession to Arianism, or to the semi-Arianism of the Eastern bishops, in order to respond in some way to the gesture of the conciliabulum of Philippopolis, which had also addressed its synodal letter to D., as bishop of Carthage; but what exactly he thought and to which among the many formulas of faith elaborated around 350 he intended to adhere, it is difficult, if not impossible, to specify now.
Bibliography
Alberto Fincherle