Synod of Worms

The Synod of Worms was an ecclesiastical synod and Imperial diet (Hoftag) convened by the German king and emperor-elect Henry IV on 24 January 1076, at Worms. It was intended to agree a condemnation of Pope Gregory VII, and Henry's success in achieving this outcome marked the beginning of the Investiture Controversy.

In 1067 Archbishop Guido of Milan, facing the rising forces of the pataria reformers in the city, gave up his see. He recommended the subdeacon Gotofredo da Castiglione his successor, who, however, was excommunicated by Pope Alexander II. While Henry IV appointed Gotofredo in 1070, the patarines elected Atto archbishop. Three years later Pope Alexander II died and was succeeded by Hildebrand of Soana, who named himself Pope Gregory VII. An ardent proponent of the papal supremacy over Henry's emperorship, he pushed the Gregorian Reform as expressed in the Dictatus papae of March 1075, including the principle that the papal title is unique in the world and that it may even be permitted to him to depose emperors.

Nevertheless, when the pataria leader Erlembald died in April 1075, all signals pointed to reconciliation. Not until Henry IV again interfered in the Milan struggles and appointed Tebald da Castiglione archbishop, as well as bishops of Spoleto and Fermo, both on papal territory, the conflict escalated. In December 1075, Pope Gregory sent a harsh letter to Henry, threatening him with excommunication.

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