Demetrios Kydones was the chief minister (Mesazon) of three Byzantine Emperors in the fourteenth century. He was a great disciple and translator of St Thomas Aquinas. He was personally in communion with the Holy See and (with his brother) a staunch opponent of the heresiarch Gregory Palamas. In this passage from his First Apology he comments on the relationship between the Emperor and the Patriarch of Constantinople.

“Among us, the patriarch is not greatly concerned about his flock. His every concern is rather how he can please the emperor. He is well aware that he holds his office only through the courtesy of the emperor, so that if the latter becomes displeased, he falls immediately from ecclesiastical office. Therefore he sees himself compelled to act like the Emperor’s slave if he is to enjoy his ecclesiastical rule for any length of time. Thus, if he makes any move to censure some cleric, or even to call some tavern owner to task, or to try to make some other feeble gesture of authority which in fact displeases the Emperor, then the injured parties run to the palace. There the Patriarch is sharply taken to task whether he vainly appeals in his defence to the gospels, the Apostles, Church law, or the Imperial edicts. Then if he does not get down on his knees to beg forgiveness, he is liable not only to lose his Episcopal see and office, but he might even be accused of treason or murder and thus be arrested as a common villain. That is the kind of servility we see inflicted on the Bride of Christ  whose freedom and independence ought to be inviolable.”