After Pepin died in 714, Redbad took part in the battle for succession in Frankish lands. He concluded a treaty with the new Neustrian mayor of the palace Ragenfrid and in 716 their armies entered Austrasian territory as far as Cologne, where they were victorious in the Battle of Cologne. In this way all lands south of the Rhine became Frisian again. The army returned to the north with much war loot. Redbad made plans to invade the Frankish empire for the second time and mobilised a large army. But before he could do this he fell ill and died in the autumn of 719.