Indulgences were a practice within the Catholic Church that allowed individuals to reduce their punishment for sins, typically in exchange for monetary donations or specific acts of piety. This practice became a significant point of contention during the Protestant Reformation, as reformers criticized it for undermining the core principles of repentance and salvation. The sale of indulgences exemplified the perceived corruption within the Church and fueled calls for reform, ultimately leading to a profound transformation in Christian practices and beliefs.