Reconstructing what iconoclasm actually was is unusually difficult, because the party that lost had its writings destroyed. The acts of the iconoclast council of Hieria survive only because they are quoted, in order to be refuted, in the acts of the council that condemned it. Iconoclast arguments reach us almost entirely inside the works of their opponents. The narrative sources are later and hostile.
Recent scholarship has used that fact to press hard on the received picture. Leslie Brubaker and John Haldon have argued that the scale, coherence and violence of iconoclasm as an imperial programme have been substantially overstated by the sources that survived, that some famous incidents are poorly attested, and that the evidence for widespread destruction of images in the first phase is thinner than the standard account assumes. Others have defended more of the traditional narrative. The debate is live.
What is not in doubt is that the question was fought over, that imperial policy moved against images for substantial periods, that the second phase ended in 843, and that the Orthodox churches still commemorate the ending each year on the first Sunday of Lent as the Triumph of Orthodoxy. The atlas records the controversy and marks the source problem, because a reader who takes the standard narrative as settled will be surprised by the current literature.