AGATHO, pope 678–681. Born in Sicily, succeeded Donus 676–678 and consecrated 27 June 678. Shortly after his election the autonomy of the church of Ravenna came to an end, which was begun in 666 by the bishop Maurus instigated by Emperor Constans II and continued by his successor Theodore. In 679 Agatho convoked a Roman council to reconfirm Wilfrid as the bishop of York, who had been expelled by the king of Northumbria Mansi 11, 179. He also sent the archcantor John abbot of St. Martin near St. Peter’s to England to promote the spread of Gregorian chant and the Roman liturgical order. Agatho granted the request of emperor Constantine IV Pogonatos sent to his predecessor Donus in 678 to send plenipotentiaries to Byzantium to resolve the monothelite question with the patriarchs of Constantinople and Antioch. The pope convened a second council at Rome in 680 for that purpose, reaffirming the condemnation of monothelitism and nominating delegates to the conference of Constantinople. With the presence of 150 fathers, papal delegates and the emperor who presided at the sessions, the conference was a true and proper ecumenical council the sixth, Constantinople III, also known as Trullo I which registered the definitive rejection of monothelitism, the reconciliation between Rome and the East, and a broad recognition of papal authority Mansi 11, 666. Agatho died before the end of the council, 10 January 681. We have two letters of his to the emperor on dyothelism forcefully reaffirmed by Rome and destined to be imposed on the universal church. His three letters to the English church are lost; another four are spurious. CPL 1737; PL 87, 1161-1248; Mansi 11, 179, 234-315, 666 and 747; MGH, Ep. III, 92; LP I, 350-358; Jaffé I, 238-240; Hfl-Lecl 3, 238- 40; H. Quentin, Les originaux latins des lettres des papes Honorius, S. Agathon et Léon II relatives au monothélisme, Misc. Amelli, Montecassino 1920, 71-76; DTC I, 559-563; DHGE I, 96-98; M. Gibbs, The Decrees of Agatho and the Gregorian Plan for York: Speculum 48 1973 213-246; S. Kutter, Implied Reference to the Digest in Pope Agatho’s Synod of 679: ZSR Rom. Abt 1990 382-384; M. Maccarone, Romana Ecclesiastica Cathedra Petri P. Zerbi – R. Volpini – A. Galluzzi, Rome 1991, 78-95; S. Kutter, “Auctor noster beatus Petrus Apostolus”: Pope Agatho on the Papal Office, Studia in hon. Eminent. Card. A.M. Stickler, Rome 1992; LTK3 1,227 G. Schwaiger; EPapi I, 612-616.
Catholic Encyclopedia: POPE ST. AGATHO travelquaz