The Investiture Controversy was a significant conflict in the 11th and 12th centuries between the papacy and European monarchies over the appointment of church officials. It centered on whether the pope or the king had the authority to invest bishops and abbots with their spiritual authority, which was crucial for both religious and political power. This struggle involved key figures such as Pope Gregory VII and Holy Roman Emperor Henry IV. The controversy highlighted the tension between secular and religious authority, ultimately leading to the Concordat of Worms in 1122, which resolved some disputes by allowing the pope to appoint bishops while granting kings the right to invest them with secular authority.