Note 129 — Chapter XXIV · : The Cathedral and Its Builders.
Reading edition
One device was to take an extra-precious relic and intrust it to monks, who would place it in a cart and drive through a wide region haranguing the faithful and holding out a purse for them to fill. At Rouen one of the cathedral towers was known as the "Butter Tower," because it was largely built with money given for permission to eat butter in Lent.