He was exiled from Wessex as a youth and during this period gathered forces and attacked the South Saxons, killing their king, Æthelwealh, in what is now Sussex.

He may have been involved in suppressing rival dynasties at this time, as an early source records that Wessex was ruled by underkings until Cædwalla.

Mul was burned in a Kentish revolt a year later, and Cædwalla returned, possibly ruling Kent directly for a period.

A major source for West Saxon events is the Ecclesiastical History of the English People, written about 731 by Bede, a Northumbrian monk and chronicler.

[1] The contemporary Vita Sancti Wilfrithi or Life of St Wilfrid (by Stephen of Ripon, but often misattributed to Eddius Stephanus) also mentions Cædwalla.

[2] Another useful source is the Anglo-Saxon Chronicle, a set of annals assembled in Wessex in the late 9th-century, probably at the direction of King Alfred the Great.

Charters were documents drawn up to record grants of land by kings to their followers or to the church and provide some of the earliest documentary sources in England.

[9] Bede states that Cædwalla was a "daring young man of the royal house of the Gewissæ", and gives his age at his death in 689 as about thirty, making the year of his birth about 659.

[5] 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".

[22][23] It may also be that the underkings were another dynastic faction of the West Saxon royal line, vying for power with Centwine and Cædwalla; the description of them as "underkings" may be due to a partisan description of the situation by Bishop Daniel of Winchester, who was Bede's primary informant on West Saxon events.

There is a King Bealdred, who reigned in the area of Somerset and West Wiltshire, who is mentioned in two land-grants, one dated 681 and the other 688, though both documents have been treated as spurious by some historians.

[18] Once on the throne, Cædwalla attacked the South Saxons again, this time killing Berthun, and "the province was reduced to a worse state of subjection".

They fled the island, but were found at Stoneham, in Hampshire, and killed on Cædwalla's orders, though he was persuaded by a priest to let them be baptised before they were executed.

[30] Cædwalla was unbaptised when he came to the throne of Wessex, and remained so throughout his reign, but though he is often referred to as a pagan this is not necessarily the most apt description; it may be that he was already Christian in his beliefs but delayed his baptism to a time of his choice.

[5] Cædwalla had not been baptised, and Bede states that he wished to "obtain the particular privilege of receiving the cleansing of baptism at the shrine of the blessed Apostles".

He stopped in Francia at Samer, near Calais, where he gave money for the foundation of a church, and is also recorded at the court of Cunincpert, king of the Lombards, in what is now northern Italy.

[34] In Rome, he was baptised by Pope Sergius I on the Saturday before Easter (according to Bede) taking the baptismal name Peter, and died not long afterwards, "still in his white garments".

[36] In 694, Ine extracted compensation of 30,000 pence from the Kentishmen for the death of Mul; this amount represented the value of an aetheling's life in the Saxon system of Weregild.