Cerularius found the issue politically useful in his conflict with the Latins. In popular opinion, the flour and water wafers of the "Franks" were not bread; their sacrifices were invalid; they were Jews not Christians. Their lifeless bread could only symbolize a soulless Christ; therefore, they had clearly fallen into the heresy of Apollinaris. The controversy became a key factor in producing the East–West Schism, which persists to this day. This question of azyms brought forth a cloud of pamphlets, and made a deeper impression on the popular imagination than the abstruse controversy of the Filioque. But it caused little or no discussion among the theologians at the Councils of Lyons and Florence. At the latter Council the Greeks admitted the Latin contention that the consecration of the elements was equally valid with leavened and unleavened bread; it was decreed that the priests of either rite should conform to the custom of their respective Church.