The Liber de Synodis, like other works in which Catholicism has endeavoured to be conciliatory, did not pass unchallenged. It satisfied neither the genuine Arian nor the violently orthodox. The notes or fragments which we call Hilary’s Apology throw light upon the latter fact. Hilary has to explain that he had not meant that the Eastern bishops had stated the true faith at Ancyra, and tells his Lord and brother Lucifer that it was against his will that he had mentioned the word ὁμοιούσιον. We must ourselves confess that Hilary puts an interpretation on the meaning of the Eastern formulæ which would have been impossible if he had written after the Synod of Ariminum. Speaking when he did, his arguments were not only pardonable but right.