 That the arts are a matter of the rational production and judgement of artifacts was widely accepted by medieval thinkers (for background, see Eco 1988, 164–165). For example, in the discussion of iconoclasm and idolatry in the Opus Caroli regis contra synodum (ca. 794), Theodulf of Orléans characterized pictures as manufacta (Noble 2009, 227, 347). Claims of this sort stood in opposition to Byzantine beliefs in such things as acheiropoeitoi, or miraculous sacred images not created by mortal hands.