c.496-537 - Following the victory at Mount Badon, the Saxon advance is halted with the invaders returning to their own enclaves. A generation of peace ensues. Corrupt leadership, more civil turmoil, public forgetfulness and individual apathy further erode Romano-British culture over the next fifty years, making Britain ripe for the final Saxon "picking."

497 - Birth of St. Cadog. Death of former King Erbin of Dumnonia.

c.500-17 - King Cadwallon Lawhir expels the Irish from Anglesey.

c.500 - Death of King Arthwys of Ebrauc. His kingdom is divided amongst his sons: Eliffer takes Ebrauc and Pabo takes the Pennines. The others may have held smaller areas.

c.505 - Death of St. Paulinus of Wales.

c.507 - A pestilence strikes Cerniw and its Royal family flee the ensuing famine. King Fracan settles in Ploufragan in Brittany and does not return. Birth of his son, St. Winwaloe. Cerniw probably falls back under the control of Dumnonia.

508 - King Cerdic of Wessex begins to move inland and defeats British king, Nudd-Lludd (Natanleod), at the Battle of Netley.

c.510 - The Battle of Llongborth (possibly Langport or Portsmouth), where King Gerren Llyngesoc of Dumnonia, was killed. Prince Riwal of Brittany murders his brother, King Meliau, and usurps the Breton throne. Many of the Breton Royal family flee to Britain, including Prince Budic who seeks refuge at the court of King Aircol Lawhir in Dyfed.

517 - Death of King Cadwallon Lawhir of Gwynedd. His son, Maelgwn takes the throne, murders his uncle, probably King Owain Danwyn of Rhos, and re-unites the two kingdoms.

517-49 - King Maelgwn flourishes in Gwynedd. Invades Dyfed and generally tries to assert himself as High-King of Britain.

519 - The Kingdom of the Wessex is founded with Cerdic, a leader probably of mixed Saxo-Celtic birth.

c.520 - King Pabo Post Prydain of the Pennines abdicates his throne in order to retire to a hermitage on Ynys Mon (Anglesey). He divides his kingdom between his two sons: Dunaut Bwr and Sawyl Penuchel. The former founds Dunoting in the North while the latter holds the Peak District in the South. Their cousin, Cynwyd, is probably forced to seek land elsewhere and establishes his own Kingdom of Cynwydion, around the Chiltern Hills. Death of King Riwal Mawr Marchou of Domnonée. King Budic II of Brittany returns to Cornouaille to claim the Breton throne.

521 - St. Samson is consecrated a bishop by St. Dyfrig, Archbishop of Glywysing & Gwent.

523 - Death of King Gwynllyw of Gwynllwg. Gwnllywg and Penychen are united under his son, St. Cadog

c.525 -St. Samson founds the Monastery of Dol and becomes its first Abbot.

c.528 - King & Saint Cadog of Glywysing abdicates in favour of King Meurig of Gwent, who is joined in marriage to Cadog's aunt. Banishment of Princess Thaney of Gododdin. Birth of her son, St. Kentigern.

530 - Saint Pabo Post Prydain, former King of the Pennines dies at Llanbabo. The British of the Isle of Wight are defeated by King Cerdic of Wessex at the Battle of Carisbrooke.

c.530 - St. Ninian founds the cathedral at Whithorn. He is opposed by King Tutgual Tutclyd of Strathclyde.

c.535 - Kings Sawyl Penuchel of the Southern Pennines is expelled from his kingdom (enemy uncertain) and flees to Powys. The Saxons of Mercia probably move into the area. Death of King Meirchion Gul of Rheged. The kingdom is divided into North and South. Death of St. Illtud, Abbot of Llanilltud Fawr.

537 - Battle of Camlann (according to the Annales Cambriae which may record the event up to twenty years late), fought between the forces of Arthur and the rebellious Medrod. Death od both. Saint and King Constantine, ruling in Dumnonia, takes on the High-Kingship.

c.538 - King Cynlas Goch of Rhos abandons his wife in favour of his sister-in-law, a nun who he drags from her convent. Civil War between Cynlas and his cousin, King Maelgwn of Gwynedd. Maelgwn enters a monastery, but soon returns to secular life and murders his nephew in order to marry his widow! Civil War also in Powys due to the tyranny of King Cyngen Glodrydd.

540 - King Jonas of Domnonée is murdered by King Cono-Mark of Cerniw and Poher. Cono-Mark marries Jonas' widow and rules Domnonée.

c.540 - Probable writing of Gildas' "De Excidio Britanniae." King Caradog Freichfras of Gwent gives Caerwent to St. Tathyw and moves the Royal court to Portskewett. Death of King Cedic of Strathclyde. His kingdom is divided between at least two of his sons: Tutgual Tutclyd retains central Strathclyde, while Senyllt receives the area around Selkirk.

545 - Death of the joint-Kings Budic II and his son Hoel I Mawr of Brittany. King Tewdwr Mawr succeeds to the throne, but is quickly ousted from Cornouaille by King Macliau of the Vannetais. Tewdwr flees to Cerniw and sets himself up as King of the Penwith region.

c.545 - The Synod of Brefi is held at Llandewi Brefi to condemn the Pelagian heresy. St. Dyfrig, Archbishop of South Wales resigns his position in favour of St. David. David moves the Archdiocese from Caerleon to St. Davids. Death of St. Dyfrig. He is succeeded as Bishop of Glywysing & Gwent by St. Teilo. Death of King Cynwyd of Cynwydion. He is succeeded by his son, Cadrod, who renames the Kingdom Calchfynedd after its chalk hills. Prince Judwal of Domnonée flees from his murderous step-father to the court of King Childebert of the Franks.

546 - St. Cadog returns to Brittany.

547 - The King of Bryneich is expelled from his fortress of Bamburgh by King Ida of Bernicia. Apparent death of the, probably joint-king, Hoel II Fychan of Brittany.

c.548 - King Cono-Mark of Cerniw, Poher and Domnonée marries Princess Triphine of Broërec.

549 - A 'Yellow' Plague hits the British territories, causing many deaths, including King Maelgwn of Gwynedd. Ireland is also affected. The Saxons in the south and east seem to be unaffected by it.

c.550 - Death of St. Ninian, Bishop of Whithorn. King Senyllt of Galwyddel is expelled from the mainland portion of his kingdom by the forces of King Tutgual Tutclyd of Strathclyde. He flees with his family to Ynys Manaw. In the confusion, Prince Gwenddoleu of Ebrauc seizes the area around Caer-Wenddoleu (Carwinley). A probable land shortage in Strathclyde forces Prince Clydno to invade Gododdin and take control of Din-Eidyn (Edinburgh). The Birth of St. Tremeur. Murder of his mother, Triphine, by his father, King Cono-Mark of Cerniw, Poher and Domnonée. Prince Judwal of Domnonée retakes his throne. Cono-Mark flees to Cornwall. The semi-legendary Kingdom of Lyonesse possibly inundated by the sea.

552 - King Cynric of Wessex lays siege to the British at Old Sarum and put them to flight.

c.553 - St. Kentigern Garthwys founds Glasgow Cathedral, adjoining a Christian cemetery established by St. Ninian at the request of the local monarch, possibly Prince Riderch Hael of Strathclyde.

c.554 - Death of King Tutgual Tutclyd of Strathclyde. The kingdom is probably divided between his sons, Morcant Mwynfawr & Riderch Hael.

555 - St. Cybi Felyn, Abbot of Holyhead, dies at his monastery. Murder of St. Tremeur. Death of his father, King Cono-Mark of Cerniw and Poher.

c.555 - Death of King Erb of Gwent. The kingdom is divided into Gwent and Ergyng. St. Kentigern Garthwys, Bishop of Glasgow, tours his diocese and is opposed by King Morcant Mwynfawr of Lesser Strathclyde.

556 - King Cynric of Wessex lays siege to the British at Barbury Castle and is victorious.

558 - Broërec is attacked by King Childebert of the Franks. King Canao II leads resistance.

c.560 - Prince Elidyr of Strathclyde invades Gwynedd in right of his wife. He tries to expel his brother-in-law, King Rhun Hir of Gwynedd, at the Battle of the Cadnant Brook, but is killed in the process. Due to heightened persecution by King Morcant Mwynfawr of Lesser Strathclyde, St. Kentigern Garthwys flees his Glasgow diocese for the safety of South Wales, before moving Northwards to Llanelwy (St. Asaphs).

564 - Death of St. Tugdual, Bishop of Tréguier.

c.564 - St. Cadog settles in Weedon in Calchfynedd and is made Bishop there. St. Samson attends the Council of Paris and witnesses several Royal decrees.

c.565 - King Riderch Hael of Strathclyde mounts an unsuccessful revenge attack on King Rhun Hir of Gwynedd. Rhun marches on Strathclyde and reinforces the armies of his half-brother, Brudei, in Pictland. Death of St. Samson. St. Gildas retuns to Ireland for a while and then retires to Llantokay (Street) in Glastening.

569 - St. David holds the Synod of Victoria to denounce the Pelagian heresy once more.

570 - Death of St. Gildas at Llantokay (Street). He is buried at Glastonbury Abbey.

c.570-75 - The Northern British Alliance is forged between the kingdoms of North Rheged, Strathclyde, Bryneich and Elmet. They fight the Northumbrians at the Battles of Gwen Ystrad and the Cells of Berwyn

571 - King Cuthwulf of Wessex invades Midland Britain and conquers the British, probably under King Cadrod of Calchfynedd, at the Battle of Bedford.

573 - Kings Peredur and Gwrgi of Ebrauc ally themselves with Kings Dunaut Bwr of the Northern Pennines and Riderch Hael of Strathclyde. They march north to claim the fort at Caer-Laverock from King Gwenddoleu of Caer-Wenddoleu. The latter was killed in the Battle of Arderydd (Arthuret) and his bard, Myrddin, is forced to flee into the Caledonian Forest.

574 - St. Kentigern Garthwys leaves his Northern Welsh diocese of Llanelwy (St. Asaphs) in the hands of St. Asaph and returns to Strathclyde to reclaim the Bishopric of Glasgow.

c.574 - After defeating King Gwenddoleu, the security of Strathclyde is at a low ebb. King Urien of North Rheged takes advantage of the situation and conquers Galwyddel.

575 - Prince Owein of North Rheged kills King Theodoric of Bernicia at the Battle of Leeming Lane.

577 - Wessex invades the lower Severn Valley. Kings Ffernfael of Caer-Baddan (Bath), Cyndyddan of Caer-Ceri (Cirencester) and Cynfael of Caer-Gloui (Gloucester) are killed at the Battle of Dyrham. Wessex overuns the Cirencester area. King Tewdwr Mawr of Brittany returns to Cornouaille, reclaims his throne and kills King Macliau of the Vannetais in battle.

580 - The army of Kings Peredur and Gwrgi of Ebrauc march north to fight the Anglians of Bernicia. Both are killed by King Adda's forces at Caer Greu. The Deirans rise up, under King Aelle, and move on the City of Ebrauc. King Peredur's son is forced to flee the Kingdom. St. Cadog is martyred in Calchfynedd by invading Mercians.

584 - Death of St. Deiniol Gwyn, Bishop of Bangor Fawr. The British are victorious over King Ceawlin of Wessex at the Battle of Fethanleigh and kill his brother, Cuthwine. Ceawlin ravages the surrounding countryside in revenge.

585 - Death of King Alain I of Brittany.

586 - Death of King Rhun Hir of Gwynedd. Death of King Judwal of Domnonée.

588 - King Edwin of Deira is ousted from his Kingdom by the Bernicians and seeks refuge at the court of King Iago of Gwynedd.

589 - Death of Saint and King Constantine of Dumnonia. Death of St. David, Archbishop of St. Davids.

590 - The Siege of Ynys Metcaut (Lindisfarne). The Northern British Alliance (North Rheged, Strathclyde, Bryneich and Elmet) lays siege to King Hussa of Bernicia and almost exterminates the Northumbrians from Northern Britain. King Urien of North Rheged is assassinated at the behest of his jealous ally King Morcant Bulc of Bryneich. The Northumbrians recover while internal squabbles tear the British Alliance apart.

c.591 - King Dunaut Bwr of the Northern Pennines mounts an invasion of North Rheged, but is repulsed by its King, Owein, and his brother, Prince Pasgen. Prince Elffin of North Rheged is simultaneously attacked by King Gwallawc Marchawc Trin of Elmet.

c.593 - King Morcant Bulc of Bryneich invades North Rheged and kills King Owein in battle. Prince Pasgen of North Rheged flees to the Gower Peninsula. A greatly diminished North Rheged probably continues under the rule of their brother, Rhun.

595 - The aging King Dunaut Bwr of the Northern Pennines dies fighting off a Bernician invasion. His kingdom is overrun and his family flee to join his grandson in Gwynedd.

598 - King Mynyddog Mwynfawr & Prince Cynan of Din-Eidyn ride south to fight Saxon Bernicia against enormous odds at the Battle of Catraeth (Catterick). The British are victorious, though King Gerren of Dumnonia is killed in the fighting. He is buried at Dingerein. Probable expansion of North & South Rheged to fill the vacuum left in North Yorkshire. Din-Eidyn (Edinburgh) possibly falls back under Gododdin control.