DONATUS. — He was not the originator, but the leader and principal instigator of the African schism that took its name from him (v. DONATISM).
The distinction between a DONATUS (the name was very common in Africa) of Casae Nigrae (*Casinenis*, *Casensis*) and one of Carthage, both Donatist bishops, is not found in the sources before the Conference of Carthage in 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 one disappears precisely when the other appears on the scene, have led various modern scholars to doubt this distinction and to reject it, following in the footsteps of Chapman; *Casae Nigrae*, in Numidia, may have been the birthplace of DONATUS.
It is also known that he wrote a letter in which he claimed that his party alone possessed valid Baptism; this was refuted by St Augustine in a work, *Contra epistulam Donati haeretici*, now 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.*, I, 1) consider to be Arianizing, or at least not precisely orthodox with regard to the Trinitarian dogma: DONATUS would 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 DONATUS made some concessions to Arianism, or to the semi-Arianism of the Eastern bishops, in order to correspond in some way to the gesture of the council of Philippopolis, which had also sent its synodal letter to DONATUS, as bishop of Carthage; but what he actually thought and to which of the many creeds elaborated around 350 he intended to adhere is difficult, if not impossible, to determine now.