In the first place virtuoso religious activists were widely perceived to exist in both Graeco-Roman and Judaeo-Christian traditions, and in the increasingly substantial overlap between them. They could function within an establishment, but were more likely to appear in opposition to it. They had substantial and prestigious precedent, a fact which frequently prejudices current and sub­ sequent perception of them. That perception is prejudiced further by the difficulties ancient and modern of distinguishing medicine, miracle and magic, which in this context function more as categories of perception than as objectively definable realities; and by the natural tendency of sources to polarise their subjects into saints and charlatans; the differences in the character and distribution of sources that cover, for example, Jesus Christ and Apollonius of Tyana militate against objective attempts at a historical consensus on the nature of either, let alone the chance of comparing them.