The Investiture Controversy or Investiture Contest was a conflict between the Church and the state in medieval Europe over the ability to choose and install bishops, abbots of monasteries, and the Pop
Henry IV begging forgiveness of Pope Gregory VII at Canossa, the castle of the Countess Matilda, 1077
Contemporary illustration of Henry IV (left) and Anti-pope Clement III (centre)
Henry IV requests mediation from Matilda of Tuscany and abbot Hugh of Cluny.
Enamel panel from Cologne figuring the investiture of a bishop (c. 1160–70), Museum für Kunst und Gewerbe Hamburg, Germany
Christianity in the 11th century is marked primarily by the Great Schism of the Church, which formally divided the State church of the Roman Empire into Eastern and Western branches.
Medallion of Christ from Constantinople, c. 1100.
Henry IV at the gate of Canossa, by August von Heyden
Victorious Byzantine cataphracts pursuing the fleeing Bulgarian heavy cavalry, from the Madrid Skylitzes
The Second Ecumenical Council whose additions to the original Nicene Creed lay at the heart of one of the theological disputes associated with the East-West Schism. (Illustration, 879-882 AD, from manuscript, Homilies of Gregory Nazianzus, Bibliothèque nationale de France)