Callixtus II
Guy of Burgundy · 1119 – 1124
Ended the Investiture Controversy by negotiating the Concordat of Worms with Emperor Henry V.
Guy of Burgundy was a French nobleman and archbishop of Vienne who became pope in 1119. His great achievement was ending the long Investiture Controversy through the Concordat of Worms in 1122, which distinguished between the spiritual and temporal aspects of episcopal appointment. He also convened the First Lateran Council in 1123, the first ecumenical council held in the West.
Why He Matters
Callixtus II found the compromise that ended one of the longest conflicts between Church and state in medieval history. The Concordat of Worms was not glamorous, but it worked — and the First Lateran Council confirmed the Church's renewed authority.