AbstractIn commemorating the Council of Nicaea, we are not looking solely at the document that it produced, nor simply the words contained in a manuscript, but the lived tradition that produced it and continues to refine our understanding. This article will therefore explore how in the century that followed the Council of Nicaea, St Cyril of Alexandria, in seeking to combat Nestorianism, in which Christ is asserted to have had distinct human and divine persons, and Mary denied the status of Theotokos (mother of God), argued not on the basis of the literal wording of the Creed of Nicaea, but on the lived tradition that produced it and continues to refine our understanding of it.