Euthymius I of Constantinople (born 834)

Euthymius I Syncellus was the Ecumenical Patriarch of Constantinople from February 907 to 15 May 912. A monk since his youth, he became spiritual father of the future emperor Leo VI the Wise, and was raised by him to the high ecclesiastical office of syncellus. Despite his turbulent relationship with Leo VI, in 907 he was appointed to the patriarchate and held the post until his deposition shortly before or after Leo VI's death in 912.