The reason for his attack is not recorded, but he may have wished to prevent King Hlothhere of Kent from regaining control of Surrey, which had been recently brought into the Mercian orbit by Wulfhere.
A razón do ataque non está rexistrada, pero puido querer evitar que o rei Hlothhere de Kent recuperase o control de Surrey, que entrara na órbita merciana grazas a Wulfhere.