The European Middle Ages represent a significant era that contributed significantly to the development of modern European culture. The problems that needed to be solved, the poor living conditions, the underdevelopment education system, and the pressure of the church and its philosophy which plunged Europe into darkness, caused people who lived in the Middle Ages to be plunged into darkness. When Stiglitz began his speech on the importance of economics, stated that “Many things on economics are not actually economic, instead they are more about ideology and religion,” makes sense here. Max Weber suggests that religion plays a key role in shaping economic activities, and true religion, albeit indirectly, can work miracles in triggering economic development. According to Ülgener, religions have been effective in regulating family relationships, family bonds, close and distant social relationships, art, policy, and many other aspects of life; and when viewed in this light, economics cannot be excluded from the religion’s field of regulation and sphere of influence. Within this context, from the birth of Jesus to the 6th century, Christianism had no impact on the economy or society. However, in later periods, developments such as the relationship and collaboration between the state and the church, the state allocating resources for donation and aid to the church, caused religion to be economically effective. Economic activities were considered fully in the religion’s field of interest in the Middle Ages, and it was suggested that these activities should be conducted under the church’s supervision. In this study, first of all, the theology of redemption and forgiveness in the Catholic faith, the indulgence practices of this forgiveness process and the abuse by the church and the papacy over time will be discussed. Afterwards, the indulgence practices of the Catholic Church in the Middle Ages will be mentioned and will be examined in terms of periodic sources. In this way, the historical and theological adventure of the most important religious exploitation practice in the history of Christianity will be tried to be revealed.