Sergius I of Constantinople

Sergius I (d. 9 December 638 in Constantinople) was the Ecumenical Patriarch of Constantinople from 610 to 638. He is most famous for promoting Monothelite Christianity, especially through the Ecthesis.

Sergius was born of Syrian Jacobite heritage. He first came to power as Patriarch of Constantinople in 610. He was also a known supporter of Emperor Heraclius, crowning Heraclius as Emperor himself in 610. Sergius also provided support to Heraclius throughout his campaign against the Persians. Sergius also played a prominent role in the defense of Constantinople against the combined Avar-Persian-Slavic forces during their invasion of Constantinople in 626. Sergius’ connections to both political and religious authorities gave him to his influence in both the religious and political communities to further Monothelitism as the primary formula of Christ within the church. This was met with much opposition, especially from that of the Chalcedonian supporters, Maximus the Confessor and Sophronius. In response to their resistance to accept the ideas of Monothelitism, Sergius responded with the Ecthesis, a formula which forbade the idea that the Person of Christ had two energies in favour of the idea that the Person of Christ had two natures that were united by a single will. The Ecthesis was signed by Heraclius in 638, the same year that Sergius died. The Ecthesis would only be seen as an accepted doctrine for two years; the death of Pope Honorius I resulted in a significant reduction in Monothelitism support. The Ecthesis was condemned in 640 by Pope John IV. Additionally, both Sergius and Pope Honorius I were condemned as heretics by the church in 680-681 by the Third Council of Constantinople.