Pope Callixtus II and Holy Roman emperor Henry V agreed the Concordat of Worms (pictured), ending the Investiture Controversy. Pope Callixtus II: Pope Callixtus II or Callistus II, born Guy of Burgundy, was the head of the Catholic Church and ruler of the Papal States from February 1119 to his death in 1124. His pontificate was shaped by the Investiture Controversy, which he was able to settle through the Concordat of Worms in 1122. September 23, 1122. Wiki link