This is a sweeping study of a literally spectacular subject: the representation of visions in the art of the Middle Ages. At the same time, it is important to be clear about what it is not. Ganz' study does not, nor, apparently, was it intended to provide a history of theories or theologies of vision and visionary experience, let alone of visions in the Middle Ages, although it does, by necessity, touch on these subjects and contributes to them in novel and interesting ways.
Nor does it dwell at any length on the history of literary representations of visionary experience, a more curious omission, given that the overwhelming bulk of the material discussed comes from illuminated manuscripts, some of which contain such texts. It would, however, be difficult to demand more of a book that is already so ambitious in scope. As Ganz notes, in the Middle Ages vision was a flexible concept that ranged in its associations and frame of reference from the empirical sense of sight corporeal vision, to use the familiar threefold Augustinian hierarchy to imaginative vision, which included dreams, memory and what medieval commentators called spiritual vision, to intellective vision: the immediate form of vision enjoyed by the angels, the souls of the just in heaven visio beatifica and, it was believed, a privileged few in this life.
Ganz focuses, as art historians must, not on the highest form of vision, which by nature remains unmediated and, hence, in large measure incommunicable, but rather on those forms of visionary experience that are mediated, that is, conveyed by some sort of intermediary. There is, however, a double mediation involved: first, that of the vision itself to the visionary whether a biblical prophet or a mystic , and second, that of their experience to their followers, readers, emulators and interpreters.
The necessity of some form of mediation, dependent on images, is precisely what led some medieval commentaries to deny vision, in whatever form, the highest rank on the scale of ways and means of knowing God. In light of their mediated or constructed character, representations of visions can thus have two closely related, but not necessarily integrated, goals: on the one hand, to share with a given audience something of what the visionary purportedly saw or experienced a process that in itself requires mediation and recreation , and on the other hand to permit members of that audience in some way to share or participate in that experience.
Bearing in mind that mysticism and visionary piety are distinct phenomena albeit to what degree is a matter of debate , the distinction drawn here is analogous to that between mystagogy, i. Another way of drawing the same distinction might be to differentiate between the object and subject of visionary experience: a visionary can have a vision of, say, the Trinity, which could be said to be the object of his or her vision and which to a believer has an objective "reality", but the subject of the same vision extends to include his or her experience, which is another matter, and has a subjective dimension.
