Propaganda, taxation and crusading ideal during the reign of Henry IV of Castile

Study of the concessions of the crusade indulgence for the fight against Granada granted in 1455 and 1456 by Pope Callixtus III to Henry IV of Castile, from the perspective of the royal propaganda and the tax benefits achieved by the Castilian monarchy, with a particular focus on the intervention of specialized fiscal agents, the quantification of the total amount obtained, and the exploitation of expenses as a weapon of political defamation