Information provided by Archenfield Archaeology
Ergyng and St Dyfrig
After the withdrawal of the Roman legions from Britain in 410 AD, new smaller political entities took the place of the centralised structure. A kingdom of Ergyng (or Ercic) seems to have been based on, and named after, the old town of Ariconium and covered what is now southern Herefordshire. To the west of Ergyng, the town of Venta (Caerwent) gave its name to the kingdom of Gwent. Beyond Gwent, Glywysing occupied modern Glamorganshire.
North of Gwent, Ewias, may have originally been a small kingdom before it became a commote of Gwent. To the north and north-west of modern Herefordshire the precursor of the Kingdom of Powys was probably centred on Viroconium (Wroxeter) the tribal city of the Cornovii.
Ergyng presumably had a Christian Church from Roman times. However, the outstanding figure in the history of the church of Ergyng is St Dyfrig, or Dubricius. Dyfrig seems to have emerged from the local Romano-British population and is said to have been born at Lann Ebrdil (Madley) in the 5th century. He began his activities at the time when the British kingdoms had a 70-year respite from Germanic incursions following their victory at Mons Badonicus (legend says under Arthur) in around 500 AD. Dyfrig founded large teaching monasteries, first at Henn Lann Dyfrig (Llanfrother near Hoarwithy) and subsequently at Mochros (Moccas). A bishopric seems to have been based at St Constantine's Church at Garthbenni (Hentland in Goodrich parish) by 500 AD.
King Erb and King Peibio
In the early 6th century Ergyng seems to have been part of a large kingdom which also included Gwent & Glywysing. The ruler of this land, King Erb, died in around AD 555, and his kingdom was divided amongst his sons.
Peibio becoming king of Ergyng. Peibio was later called "the dribbler" but this may be an error based on the similarity between the old Welsh word for dribbling and the word for leprosy. If Peibio did suffer from leprosy, so did many other people — it would be many centuries before leprosy disappeared from the British Isles.
In the east of Britain, Germanic invaders were overrunning the Romanised native people. There has been a lot of speculation about the numbers of the Germanic Anglo-Saxons who came to Britain. DNA analysis of modern males suggests that the British population was totally swamped in large areas of the country. Powys seems to have lost its eastern territories (in modern Shropshire) to an expanding Mercia, the Anglian kingdom based in the midlands. In 577 the Saxons defeated the British at the Battle of Dyrham, and captured Bath, Cirencester and Gloucester.
Pont y Saeson and the Last Kings of Ergyng
The British king Tewdrig's victory at the Battle of Pont y Saeson on the lower Wye in around 620 or 630 stopped their advance and South Wales was never again to be seriously threatened by the English peoples.
In Ergyng, King Peibio was followed by Cinuin and Gwyddgi, who were followed in turn by Gwrgan. Gwrgan is the last person recorded as King of Ergyng, and probably died in about 645. Gwrgan's daughter, Onbraust, married Meurig of Glywysing/Gwent, and their son Athrwys became king of both kingdoms.
King Merewalh
Not very much is known about Herefordshire north of the Wye in this period. Leominster seems to have been an early British church (Llanllieni) but how and when this territory became dominated by the Anglo-Saxons is almost totally obscure.
In the mid 7th century the area which is now northern Herefordshire and southern Shropshire was ruled by a king named Merewalh. His people were the Western Hecani, who are often equated with the Magonsaetan, although this name is not known before the 10th century. Merewalh was a sub-king beneath Penda, King of Mercia.
Unlike the kings of Ergyng, with its Christian church with origins in Roman times, King Merewalh was a pagan. It is however possible that the people he ruled were Christian — there are no known pagan Anglo-Saxon burials or cremation anywhere in this area. The mission to the English begun by St Augustine in 597 was still in an early stage.
Etfrid the Monk
A Northumbrian monk named Etfrid is said to have converted Merewalh to Christianity in 660. The Northumbrian church at that time would have had similar, though possibly not identical practices to the other British churches. Easter would have been celebrated at the same time in Leominster and Moccas. This changed after the Synod of Whitby in 663, when the Northumbrian church adopted the Roman Easter. From this time, what is now northern Herefordshire held to a different Easter from what is now southern Herefordshire, and would continue to do so until the church in the West (that of Wales) changed to the Roman calendar a century later (768 AD).
Merewalh's sons, Merchelm and Mildfith were also rulers of this people. After them there is no further mention of sub-kings and presumably this area became directly under the control of the Mercian kings.
Ithel ap Morgan
Herefordshire was the scene of border warfare throughout the early 8th century. In 722 King Ithel ap Morgan of Glywysing won a victory over the Mercians at Pencoyd in Ergyng. The spoils of this warfare are hinted at in the purchase price of some land in Ergyng at this time, which included "a Saxon woman, a precious sword and valuable horse".
In 743 Cuthred of Wessex joined the Mercian king, Aethelbald, and Ergyng was laid waste. By 745 Ithel had regained control of the area and returned 11 churches there to the Bishop of south-eastern Wales, Berthwyn.