Coup d'état of Kaiserswerth

The Coup of Kaiserswerth (German: Staatsstreich von Kaiserswerth) in 1062 was a hitherto unprecedented action of several secular and ecclesiastical Princes of the Holy Roman Empire under the leadership of Archbishop Anno II of Cologne against Empress Agnes, ruling on behalf of her under-age son, King Henry IV, and against her chosen sub-regent, Bishop Henry II of Augsburg. By kidnapping the young king and enforcing the handover of the Imperial Regalia, the group gained control of the reins of power in the Empire.

In early April 1062, eleven-year-old Henry IV and his mother were staying in the Königspfalz of Kaiserswerth (today a quarter in Düsseldorf), erected by Agnes' late husband Emperor Henry III, where both met with Archbishop Anno II of Cologne. After banqueting together, Anno invited the boy to visit a magnificent ship that he had moored in the River Rhine nearby. What Henry experienced when he boarded the ship, is related by the contemporary chronicler Lambert of Hersfeld as follows:

Anno then took the king up the river to his Cologne residence and blackmailed Empress Agnes to hand over the Imperial Regalia. As a consequence the power of the state fell into the hands of the rebels, who, in addition to Anno and Count Egbert of Brunswick, mentioned by Lambert, also included Otto of Northeim as well as the Archbishops Adalbert of Bremen and Siegfried of Mainz.

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