History of Christianity
The Investiture Controversy, also known as the lay investiture controversy, was the most important conflict between secular and religious powers in medieval Europe. It began as a dispute in the 11th century between the Holy Roman Emperor Henry IV and Pope Gregory VII. The question was who would control appointments of bishops (investiture). The end of lay investiture meant an important loss of royal power, and a loss for ambitious noblemen, for the benefit of Church reform as the pope intended.