To a medieval devotee, things are agents and representations; but they are more. They are likenesses ontologically (that is, as what they are). Incense is really like the rising up of a prayer; gold is really like heavenly light or power in more than an arbitrary or simply attributed sense. The veil and crown of a nun do not merely symbolize her virginity; they are her intactness. The flesh of Francis of Assisi is not only nail-like; it has literally become Crucifixion nails, even if Francis, despite being known as the alter Christus, does not become Christ. Although the stigmata of Francis, the bloody wafer of a host-desecration miracle, the tooth of a saint presented in crystal, the nun’s habit, and the gold of a statue’s crown are not “like” the Other of heaven and of God in the same way, they are not simply symbols, icons, or indexes. All are “like” the holy ontologically—that is, in more than an assigned or arbitrary, literal or purely visual sense.
Caroline Walker Bynum, Dissimilar Similitudes: Devotional Objects in Medieval Europe
