Bretwalda in the context of "Edwin of Northumbria"

Ecgberht (died 839), also spelled Egbert, Ecgbert, Ecgbriht, Ecgbeorht, and Ecbert, was King of Wessex from 802 until his death in 839. His father was King Ealhmund of Kent. In the 780s, Ecgberht was forced into exile to Charlemagne's court in the Frankish Empire by the kings Offa of Mercia and Beorhtric of Wessex, but on Beorhtric's death in 802, Ecgberht returned and took the throne.

Little is known of the first 20 years of Ecgberht's reign, but it is thought that he was able to maintain the independence of Wessex against the kingdom of Mercia, which at that time dominated the other southern English kingdoms. In 825, Ecgberht defeated Beornwulf of Mercia, ended Mercian Supremacy at the Battle of Ellandun, and proceeded to take control of the Mercian dependencies in southeastern England. In 829, he defeated Wiglaf of Mercia and drove him out of his kingdom, temporarily ruling Mercia directly. Later that year Ecgberht received the submission of the Northumbrian king at Dore. The Anglo-Saxon Chronicle subsequently described Ecgberht as a bretwalda or 'wide-ruler' of Anglo-Saxon lands.

Augustine of Canterbury (early 6th century – most likely 26 May 604) was a Christian monk who became the first archbishop of Canterbury in the year 597. He is considered the "Apostle to the English".

Augustine was the prior of a monastery in Rome when Pope Gregory the Great chose him in 595 to lead a mission, usually known as the Gregorian mission, to Britain to Christianize King Æthelberht and his Kingdom of Kent from Anglo-Saxon paganism. Kent was likely chosen because Æthelberht commanded major influence over neighbouring Anglo-Saxon kingdoms in addition to his marriage to Bertha, a Frankish princess, who was expected to exert some influence over her husband. Before reaching Kent, the missionaries had considered turning back, but Gregory urged them on, and in 597, Augustine landed on the Isle of Thanet and proceeded to Æthelberht's main town of Canterbury.

Rædwald (Old English: Rædwald, pronounced [ˈrædwɑɫd]; 'power in counsel'), also written as Raedwald or Redwald (Latin: Raedwaldus, Reduald), (died c. 624) was a king of East Anglia, an Anglo-Saxon kingdom which included the present-day English counties of Norfolk and Suffolk. He was the son of Tytila of East Anglia and a member of the Wuffingas dynasty (named after his grandfather, Wuffa), who were the first kings of the East Angles. Details about Rædwald's reign are scarce, primarily because the Viking invasions of the 9th century destroyed the monasteries in East Anglia where many documents would have been kept. Rædwald reigned from about 599 until his death around 624, initially under the overlordship of Æthelberht of Kent. In 616, as a result of fighting the Battle of the River Idle and defeating Æthelfrith of Northumbria, he was able to install Edwin, who was acquiescent to his authority, as the new king of Northumbria. During the battle, both Æthelfrith and Rædwald's son, Rægenhere, were killed.

From around 616 Rædwald was the most powerful of the English kings south of the Humber estuary. According to Bede, he was the fourth ruler to hold imperium over other southern Anglo-Saxon kingdoms: he was referred to in the Anglo-Saxon Chronicle, written centuries after his death, as a bretwalda (an Old English term meaning 'Britain-ruler' or 'wide-ruler'). He was the first king of the East Angles to become a Christian, converting at Æthelberht's court some time before 605, while also maintaining a pagan temple. He helped Christianity to survive in East Anglia during the apostasy of the Anglo-Saxon kingdoms of Essex and Kent. Historians consider him the most likely occupant of the Sutton Hoo ship-burial, although other theories have been advanced. A smaller ship-burial was also discovered in 1998 close to the original Sutton Hoo site, which is thought to have contained the body of his son Rægenhere, who died in battle in 616.

Æthelbald (also spelled Ethelbald or Aethelbald; died 757) was the King of Mercia, in what is now the English Midlands from 716 until he was killed in 757. Æthelbald was the son of Alweo and thus a grandson of King Eowa. Æthelbald came to the throne after the death of his cousin, King Ceolred, who had driven him into exile. During his long reign, Mercia became the dominant kingdom of the Anglo-Saxons, and recovered the position of pre-eminence it had enjoyed during the strong reigns of Mercian kings Penda and Wulfhere between about 628 and 675.

When Æthelbald came to the throne, both Wessex and Kent were ruled by stronger kings, but within fifteen years the contemporary chronicler Bede describes Æthelbald as ruling all England south of the Humber estuary. The Anglo-Saxon Chronicle does not list Æthelbald as a bretwalda, or "Ruler of Britain", though this may be due to the West Saxon origin of the Chronicle.

Æthelberht (/ˈæθəlbərt/; also Æthelbert, Aethelberht, Aethelbert or Ethelbert; Old English: Æðelberht [ˈæðelberˠxt]; c. 550 – 24 February 616) was King of Kent from about 589 until his death. The eighth-century monk Bede, in his Ecclesiastical History of the English People, lists him as the third king to hold imperium over other Anglo-Saxon kingdoms. In the late ninth century Anglo-Saxon Chronicle, he is referred to as a bretwalda, or "Britain-ruler". He was the first Anglo-Saxon king to convert to Christianity.

Æthelberht was the son of Eormenric, succeeding him as king, according to the Chronicle. He married Bertha, the Christian daughter of Charibert I, king of the Franks, thus building an alliance with the most powerful state in contemporary Western Europe; the marriage probably took place before he came to the throne. Bertha's influence may have led to Pope Gregory I's decision to send Augustine as a missionary from Rome. Augustine landed on the Isle of Thanet in east Kent in 597. Shortly thereafter, Æthelberht converted to Christianity, churches were established, and wider-scale conversion to Christianity began in the kingdom. He provided the new church with land in Canterbury, thus helping to establish one of the foundation stones of English Christianity.