Up to now we have looked mostly at differing teachings about the human person and especially tendencies to separate it into warring factions. When this fractured view of humanity is taken into the Christological arena it becomes heresy; the conflicts or divisions between component parts within the human person present no major doctrinal problems until ecclesiastical debates about original sin begin to be formulated. If, as Nicaea and Chalcedon insist, Christ’s humanity must be full and entire, then his fleshly body must be combined with the soul, mind and spirit, since all these are part of the make-up of the human person. The Christological heresies which led to the doctrine of the dual nature variously undermined the full humanity of Christ, and, in so doing, denigrated those parts of humanity which they attempted to exclude from Christ’s humanity. The teachings of the desert urged spiritual athletes to ‘fight[ing] manfully against the passions of both body and soul’, according to Cyril’s Letter to the Monks of Egypt.1 The same author was to crystallise the integration of body and soul in Christ, through his operations in the public arena of Ecumenical Councils.