What was the Investiture Controversy about?

Explanation

The Investiture Controversy was a conflict in the Middle Ages in the 11th and 12th centuries between the Holy Roman Emperors on one side and the Popes on the other side and was about the control of appointments to positions such as bishops, abbots, etc. The controversy came to an end in 1122 with the Concordat of Worms (Pactum Calixtinum) which strengthened the papal in the short run, though not in the longer term.