Another indication of the political and military situation may be the division in the 660s of the West Saxon see at Dorchester-on-Thames; a new see was established at Winchester, very near to the South Saxon border. Bede's explanation for the division is that Cenwalh grew tired of the Frankish speech of the bishop at Dorchester, but it is more likely that it was a response to the Mercian advance, which forced West Saxon expansion, such as Cædwalla's military activities, west, south, and east, rather than north. Cædwalla's military successes may be the reason that at about this time the term "West Saxon" starts to be used in contemporary sources, instead of "Gewisse". It is from this time that the West Saxons began to rule over other Anglo-Saxon peoples.