The eucharistic crisis of the eleventh century posed the greatest challenge to the Church's understanding of the Real Presence of Christ in the Blessed Sacrament until the Reformation. The eucharistic symbolism of Berengarius of Tours, which was at the heart of the controversy, was challenged first by Lanfranc of Canterbury and then by his student Guitmund of Aversa. Both authors countered with a vigorous defense of the Church's traditional belief...