Pope Formosus
Recognising the superiority of Arnulf's position, in 888 king Odo of France formally accepted the suzerainty of Arnulf. In 893 Arnulf switched his support from Odo to Charles the Simple after being persuaded by Fulk, Archbishop of Reims, that it was in his best interests. Arnulf then took advantage of the following fighting between Odo and Charles in 894, harrying some territories of West Francia. At one point, Charles the Simple was forced to flee to Arnulf and ask for his protection. His intervention soon forced Pope Formosus to get involved, as he was worried that a divided and war weary West Francia would be easy prey for the Vikings.