(2 Nov. 676–11 Apr. 678)
A Roman by birth, son of Maurice, he was already elderly when elected; he had only to wait a few months before receiving the imperial mandate necessary for his consecration. His reign is even more obscure than that of Adeodatus II, but it is known that he reached an accommodation (although it remained for the moment a dead letter) with Reparatus, archbishop of Ravenna, which implied the abandonment by that see of its claim to autocephalous status and independence from Rome, granted by Emperor Constans II (641–68) in 666. In Rome itself he had the shock of discovering that the Syrian monks occupying a well-known monastery were in fact Nestorians; he replaced them by orthodox Roman monks and dispersed them among other monasteries in the hope that they might be converted to the Chalcedonian doctrine. Meanwhile there was a growing desire in Constantinople for the restoration of unity with the holy see, for decades interrupted by the monothelite controversy, and Emperor Constantine IV (668–85) put pressure on Patriarch Theodore I (677–9), who as a monothelite was initially reluctant, to write to Donus, not enclosing the customary profession of faith but expressing his desire for amicable relations. Constantine himself addressed (12 Aug. 678) a courteous and conciliatory letter to the pope inviting him to send delegates to a conference which would thrash out the disputed theological issues; his exarch would provide transport and pay expenses. Donus, however, was dead before the letter left Constantinople. Little else is known of his reign except that he was active in building, restoring, and embellishing churches; among other works, he adorned the atrium before St Peter's with a marble pavement. He was reportedly generous to his clergy.
JW i. 238LP i. 348 f. (Davis 1: 75–6)FD i n. 242Mansi xi. 196–201Caspar ii. 585–8DHGE xiv. 671 f. (H. Marot)NCE iv. 870 (C. M. Aherne)Bertolini 365–7Levillain i. 514–15 (J. Durliat)Seppelt ii. 71JR 198