In 359 the Emperor Constantius assembled the council of Rimini, a city of Central Italy. Six hundred bishops and a number of priests now undo all that the council of Nice had done. This council was as accommodating to Arian Constantius as to the Trinitarian Constantine. Constantius, forsaking the Trinitarian system, adopted Arianism, and Greeks and Latins complied with the imperial wishes, and, like dutiful subjects, signed the Arian and semi-Arian confessions of Sirneium, Seleucia, Milan and Ariminum. The western and eastern prelacy subscribed in compliance with their sovereign to the Arian creed, which, as Du Pin has shown, was signed by his infallibility, Pope Liberius.
Next in our programme comes Theodosius I., assembling a council of one hundred and fifty bishops at Constantinople in the year 381. Theodosius was a zealous Catholic; he was baptized before the end of the first year of his reign, and immediately published an edict in support of the doctrine of the Trinity, branding all who did not hold it as heretics. His council was presided over by St. Gregory Nazianzen. The chief work of this council was to anathematise the Council of Rimini, which was composed of six hundred bishops and a multitude of priests. This work was done, and so one hundred and fifty bishops curse and denounce as heretical and false six hundred bishops and a multitude of priests; so the voice of the many is not always the voice of God, nor yet the voice of a council the voice of a Pope; neither is the infallibility of a Pope always found in a council, nor is the infallibility of one Pope always found in the voice of another.