Ane Bysted :
The emergence and conceptual development of the Crusade-indulgence.

Indulgences were granted to participants in every medieval crusade, but only slowly did this privilege take on a standard form. In lack of a fixed vocabulary the early indulgences were expressed by employing older concepts, and this obscures their meaning, but considered in the context of 10th and 11th century understanding of penance it seems likely that they were intended to have a transcendental effect. However, the papal proclamations of crusade-indulgences indicate a growing confidence in the authority of the Church to grant these remissions of penance in the sight of God. The theological explanations developed rather late, but were to further emphasize this authority with the doctrine of the treasury of merit and to reaffirm papal authority to promise the crusaders a spiritual reward.