Don·a·tist 
(dŏnə-tĭst, dōnə-)
(dŏnə-tĭst, dōnə-)n.
A member of a rigoristic, schismatic Christian sect, strongly opposed by Saint Augustine, that arose in North Africa in the fourth century AD and believed in sanctity as requisite for church membership and administration of all sacraments.
[Medieval Latin Donatista, after Donatus, fourth-century AD ecclesiastic and rival claimant of the bishopric of Carthage.]
Dona·tism n.