Treaty of Bonn

[1][2] The use of the river, which was the border between their two kingdoms, as a neutral territory had extensive Carolingian precedents and was also used in classical antiquity and in contemporary Anglo-Saxon England.

[3] The treaty, which "more than most such amicitiae, was decidedly bilateral, reciprocal and equal", recognised the border of the two realms and the authority of their respective kings.

In the treaty, Henry is titled rex Francorum orientalium (King of the East Franks) and Charles rex Francorum occidentalium (King of the West Franks) in recognition of the division it made of the former Frankish Empire.

In January or early February 923, Henry made a pact of amicitia with the usurper Robert I against Charles, who subsequently sent a legate to Henry with the relic of the hand of Dionysius the Areopagite, sheathed in gold and studded in gems, "as a sign of faith and truth [and] a pledge of perpetual union and mutual love" in the words of Widukind of Corvey.

[5] Charles probably intended to recall Henry to the terms of the treaty of Bonn and draw him away from Robert.