Cap and Trade

"...John XXII, who assumed the office (of Pope) in 1316, and gave the papacy a thoroughly materialistic cast. It was John who developed, if he did not devise, the widespread system of remitting sins by the sale of indulgences, which allowed anyone with money to sin with impunity, so long as he could pay the "fine". Such fines (as commutation of punishment) were based in part on the doctrine of the superabundant merits of the saints, who were supposed to have been better than they needed for their own salvation. Their excess credits could therefore be stored in a celestial deposit box called the "Thesaurus meritorium sanctorum" (Compendium of the Merits of the Saints), and from this treasury "the pope could draw and make transfers to anyone whose account happened to be deficient". At the same time, this treasury could never be exhausted because its assets included the inexhaustible merits of Christ. So there was no end to the indulgences the pope could sell."

(from Wide as the Waters: The Story of the English Bible and the Revolution It Inspired -- Benson Bobrick)