Thus the "Willhelminer War", that was to last until 884, led to the devastation of Pannonia east of the river Rába. Finally, Charles the Fat himself turned up and received Svatopluk as his man at Kaumberg (Germany), receiving promises of peace and fidelity. Svatopluk also promised never to invade Charles the Fat's realm with a hostile force as long as he lived, while Charles the Fat recognized him as a prince of his realm. Peace between Arnulf and Svatopluk, however, was only sealed in the latter part of the following year.