 Eventually, Cædwalla invaded the kingdom of the South Saxons and slew King Æðelwealh.Æðelwealh's successors, Berthun and Andhun, drove Cædwalla out, but after the death of Centwine, Cædwalla was able to become King of the West Saxons.He then conquered the South Saxons, killing Berthun in the process.