The topic of indulgences that the faithful received after supporting the Hospitallers from the island of Rhodes fighting against the Turks has not aroused much interest in Polish historiography so far, even though it has been of interest to researchers from Western Europe for a long time. Out of over 1,539 registered indulgence documents from the territory of the Kingdom of Poland, only a few of them concern this issue. These awards have common features that allow them to be distinguished from other diplomas in which the Pope, bishops and legates encouraged the faithful to take part in the crusades. By virtue of the decisions of the ecumenical councils, the faithful who decided to accept the cross or financially supported the crusade received a plenary indulgence, were also subject to the protection of the Holy See during the expedition, and gained a number of further privileges.