Ruled c580 - 24 February 616.
Married: (1) c578, Bertha (c560-c602), dau. Charibert, king of Pans; (2) second wife unknown.
Athelbert is the first Anglo-Saxon king about whom we have some strong historical facts, although even these are inconclusive about the length of his reign or of his life. The ASC records his birth as being in 552, which could be right, though if he died in 618 he would be aged 66 and not 56 as suggested by Bede (Bede's reference is ambiguous and the 56 years has been interpreted as the length of his reign rather than his life). Other evidence, particularly that related to his marriage to Bertha, narrow the limits of his reign, but still give us a picture of a strong and wealthy king. Athelbert was the son of EORMENRIC whose alliance with the Merovingian Franks had brought both stability and wealth to the kingdom of Kent. Athelbert's sister, Ricula, had married the king of Essex (see SLEDDA), over whose territory Athelbert was overlord. Athelbert soon became regarded as the bretwalda or overlord of the other Saxon domains. This extended over the kingdoms of the East Angles, Lindsey, Mercia, the Middle Angles and to some extent the West Saxons. Athelbert's reign coincides with the first great period of Saxon domination after the death of ARTHUR and the expulsion of the remnant British Celts from the heartland of Britain. Although battles continued in the north and west, Kent remained comparatively free of conflict, and this allowed Athelbert to increase the wealth and influence of his kingdom. It is possible that early in his reign he had some expansionist skirmishes with CEAWLIN of the West Saxons - though the date recorded in the ASC (568AD) is wrong if it refers to Athelbert, it might refer to his father or to an incident early in Athelbert's reign (say around 583) which was a setback for Athelbert but only a temporary victory for Ceawlin.
It was thus especially significant that Athelbert was the first Saxon king to embrace Christianity. He already had sympathy with the religion because his wife was Christian and part of the marriage arrangement was that her chaplain, Liudhard, should accompany her. Liudhard was allowed to restore the old Roman church of St Martin's at Canterbury which had stood for some two centuries. Athelbert was initially cautious in welcoming the mission of Augustine who was sent by Pope Gregory I to convert the Saxons. Augustine landed at Thanet in 597 and was met by Athelbert under an oak tree which the Saxons venerated and which he believed would cancel any magic the Christians might practice. Athelbert recognized the sincerity of Augustine but declared he could not abandon the religion of his fathers. Nevertheless he allowed Augustine and his colleagues to establish a house at Canterbury, where they used Liudhard's church of St Martin's, and within a short period many hundreds of Athelbert's subjects were baptized. Athelbert himself was not baptized until 601, but thereafter he became fervent in his support. He actively encouraged Augustine to establish another church, in west Kent at Rochester, and a third in London, the original St Paul's. It was a sign of Athelbert's authority as bretwalda that he was able to organize a meeting between Augustine and the Celtic church, at a place later known as Augustine's Oak on the borders of Gloucestershire and Somerset, as part of Augustine's plan to bring the Celtic church under Roman authority. Unfortunately it failed because of Augus-tine's arrogance and, by association, it dented Athelbert's power.
With the help of Augustine, Athelbert established a set of law codes, which formed the basis of those later developed by OFFA and ALFRED. These had the innovation of giving particular protection to the church, but were otherwise probably developed from existing Frankish laws. They went into immense detail, bringing in a system of monetary fines (rather than payment in kind, such as livestock), allowing people to pay in instalments, and establishing the level of fine in accordance with the severity of the crime. The king was reckoned as overlord so that if any crime were committed within his kingdom, the perpetrator had to recompense the king as well as the victim (or victim's family). The law also gave considerable protection to women and allowed a wife to leave her husband if there was good cause, although the husband had the final say as to who kept the children. These laws not only restored a form of governance and administration to Britain, but with the emphasis on monetary compensation, also reinstituted a financial system. Coins were based on the Frankish design and Athelbert established a mint at Canterbury to produce his own coinage. He introduced the silver sceat as the common basis of coinage, the nearest equivalent to a penny, as a twentieth part of the gold solidus, or shilling.
Under Athelbert Kent became not only the most sophisticated, but in all probability the safest of Saxon kingdoms in England, and that in turn allowed it to become the wealthiest. This would have made it the envy of the other Saxon kings, particularly in the emerging states of Wessex and Mercia, so that it needed a strong monarch to sustain it. Athelbert was such a strong monarch, which was why he was acknowledged as bretwalda for much of his reign (probably from about 588), but he needed strong successors if his kingdom's power was to remain. Unfortu-nately that did not happen. His son, EADBALD, was a different character; he turned his back on Christianity and the power of Kent faded. Nevertheless, the Christian message was sustained by Athelbert's daughter, Athelburh, who married EDWIN of Northumbria, and introduced Christianity to the northern Angles. Athelbert was later venerated as a saint. A small cult developed in Kent, probably soon after the king's death, but the main centre of his worship developed in the thirteenth century. Not only was he the first Saxon saint in Britain he was, more significantly, the first Saxon king to be so venerated.