Карл III Толстый
He supported Arnulf of Carinthia's claim to the kingdom of East Francia after the deposition of Charles the Fat in 887. He was a close relative of the Ahalolfings, a prominent family in Alemannia. Richardis, the repudiated wife of Charles the Fat, was an Ahalolfing. It is possible that Rudolf's support for Arnulf stemmed from the treatment Richardis had received from Charles.