What major controversy involved the power struggle over the investment of bishops?

The major controversy involving the power struggle over the investment of bishops is known as the Lay Investiture Controversy. This significant conflict arose in the late 11th and early 12th centuries, primarily between the papacy and various monarchies over the appointment of church officials, including bishops.

At the heart of the issue was whether secular leaders (laypersons) had the authority to appoint bishops and confer upon them the symbols of their office (investiture) or whether this authority belonged solely to the church and, specifically, to the pope. This struggle highlighted the tension between spiritual authority and temporal power, as rulers sought to maintain control over the church within their realms to ensure loyalty and strengthen their governance, while the pope aimed to assert the church’s independence from political interference.

The resolution of this controversy eventually led to the Concordat of Worms in 1122, which established a compromise: only the pope could invest bishops with spiritual authority, while the emperor retained the right to invest them with temporal authority. This landmark agreement significantly shaped the relationship between church and state in medieval Europe.