The exchanges of 357-8 inflicted some damage on Constantius' ambitions for peace in the Church, especially by creating distrust of his policies among western bishops. This distrust was mightily fostered by the banished Hilary of Poitiers, whose exile in Phrygia did not prevent him writing letters to Gaul. Late in 358 he wrote for the Gallic bishops a weighty tract 'on the synods or concerning the faith of the Orientals' (De synodis seu de fide Orientalium). His principal purpose was not merely to tell the uninformed about eastern creeds but also to urge generous western sympathy for Basil's homoiousian group and to explain to the latter that western theology was not Sabellian. He argued that the term homoiousios is far from being incompatible with the Nicene formula. The statement of faith from Sirmium in 357, despite its pointed insistence on scriptural authority for each affirmation including the subordinate status of the Son, Hilary presented in lurid colours as the 'blasphemy' of Sirmium and in some degree caricatured by glosses to the effect that Christ is presented as created out of nothing, which the document never says. Because the extreme Arian party of Aetius and Eunomius regarded the statement as granting them citizenship rights of toleration, it was natural to attribute to the statement a radicalism which was not there.
Hilary readily conceded that the Nicene homoousios provided cover for Sabellian modalism and could be understood in a way 'as much wrong as right' (Syn. 67). A correct understanding takes Father, Son, and Spirit not to be hierarchically graded but to be equal and therefore one; but not one person with two names, and not one substance which is then split up into two halves. An erroneous view understands the one substance to be a prior substance in which the two persons Father and Son participate. But if homoousios is ambiguous, so too is homoiousios since likeness normally implies some measure of dissimilarity; a vessel may be plated with gold so as to be very similar (Syn. 89). The sacredness of the Nicene homoousios is sure from the tradition