The early Church kept alive the pre-Christian belief in the supernatural significance of dreams. The pagan practice of seeking foreknowledge by ritual incubation (sleeping over) at the shrine of Asklepios, the god of healing, was replaced with nocturnal vigils at the shrines of Christian saints. Vigils were also kept in churches on the eve of the feast day of their patron saints, and on the eves of great annual festivals. It was important to be wakeful across the temporal divide of midnight, the transition from one day to the next. This was the moment when the epiphany began, the descent of divinity to the sacred place.

Jennifer Westwood, On Pilgrimage