The quest for truth, foreseeing the future, solving the enigmas of the past, finding answers to acute questions: all this was promised by oracles already in antiquity. Although the rise of Christianity meant a break with this tradition, the art of fortune telling continued to thrive, partly based on models from antiquity but in Christianized form, partly using genuinely new methods in medieval times. The secret scholarly treatises on oracle techniques, which were only reluctantly tolerated by the church, were always subject to prohibition, since theologians condemned the belief in fate and...