Cyriacus II of Constantinople

Cyriacus II (d. 29 October 606) was the 30th Ecumenical Patriarch of Constantinople (595–606). Pope Gregory I received the legates bearing the synodal letters which announced his consecration, partly from a desire not to disturb the peace of the church, and partly from the personal respect which he entertained for Cyriacus; but in his reply he warned him against the sin of causing divisions in the church, clearly alluding to the use of the term oecumenical bishop, which Gregory interpreted as meaning "universal" or even "exclusive" bishop. The personal feelings of Gregory towards Cyriacus appear most friendly. He appears to have been a man of remarkable piety and earnestness, able to win the esteem of all parties.

Cyriacus II in Thessalonica
Father Luke, sentenced to penance, would have written to Patriarch Cyriacus if he had thought Bishop Eusebius' decree too harsh. However, he didn't, and felt that Eusebius was in the right when he penalized Luke for making an alliance with ancient Greek demigods against the barbarian invasions. Luke told George the shoemaker that he had no intention to involve Cyriacus.