This timeline spans events from Roman Britain to the present time; thus, all events are A.D. Some dates are for non–historic events (i.e., mythical).
Year Event
360 Picts and Scots cross Hadrian's Wall and attack Roman Britain; brief British pagan revival in countryside as reaction to Emperor Julian's rejection of Christianity.
363 End of Julian's reign.
364 Roman Empire divides into East (based at Constantinople) and West (still centered on Rome); Valentinian I emperor in West.
367 Northern Confederation launches series of attacks on lines of Roman fortifications until 383— Hadrian's Wall overrun, Count of Saxon Shore and Duke of Britain crushed.
369 Valentinian sends Theodosius to restore order in Britain.
370 Theodosius drives Picts and Scots out of Britain, restores walls and forts, establishes signal stations along the Yorkshire coast, giving peace to towns and villas for at least a quarter of a century.
375 End of the reign of Valentinian I.
378 Adrianople falls to the Visigoths; beginning of the reign of Theodosius I.
382 Magnus Maximus repels the Caledonians at Hadrian's Wall.
383 Magnus crosses the channel to assert his claim on the purple, taking many of the British troops; consequentially northern Britain is threatened by Picts and Scots although Hadrian's Wall holds; Conan is king in Brittany.
388 Magnus is executed, along with son Victor.
c. 390 Saint Patrick is born on west coast of Britain.
392 Theodosius reunites the Empire.
395 Empire redivides; Theodosius dies and 10–year–old Honorius made emperor.
396 Northern Confederation launches offenses across the firths; General Stilicho sent to campaign against the Caledonians.
c. 397 Founding of Western monasticism; St. Ninian builds Candida Casa. Rome completes withdrawal from Hadrian's Wall.
401 Troops withdrawn from reaches of the Empire to defend Italy against Visigoth Alaric.
405 Niall of the Nine Hostages dies.
406 Britons elect Marcus and then Gratian to the purple, who are both quickly executed.
407 Constantine III crosses to the continent with all the troops he can muster; Burgundians penetrate far into Gaul and Spain, cutting off communication between Britain and Rome; Saint Patrick escapes slavery in Ireland.
410 Alaric invades and sacks Rome; beginnings of alchemy with the search for the Philosopher's Stone and the Elixir of Life; Honorius sends message to Britain that it is on its own.
411 Constantine III is slain.
417 Temporary Roman reoccupation (theory— improbable)
418 Pelagianism is ruled heresy by the church
423 End of the emperor Honorius' reign.
425 Beginning of Saint Patrick's ministry in Ireland and Saint Illtud's ministry in Wales.
426 Emergence of local leaders in Britain, such as Vortigern.
428 Saxon warships off east coast of Britain
429 Picts and Scots expelled from Southern England by Saxon mercenaries; Saints Germanus and Lupus are sent to Britain to conquer Pelagianism.
432 Roman currency no longer in circulation; Saint Niniane dies.
440 Town of Ys in Brittany submerges.
441 Beginning of Saxon incursion.
442 Hengist's massacre.
446 Last British request for military aid, sent to Aetius.
449 Germanus and Lupus sent again to conquer Pelagianism.
450 Anglo–Saxon warships attack Britain's east coast.
451 Attilla and the Huns invade Western Europe; St. Genevieve saves Paris.
456 Britons suffer a defeat by the Saxons at Crayford, Kent, and flee to London.
460 Presumed start of Aurelius Ambrosius' reign.
461 Saint Patrick dies.
462 Saint David, patron saint of Wales (462–547)
480 Reign of King Cerdic of "Wessex" (fl. 480–495)
482 Battle of Ocha in Ireland.
491 Saxons capture Pevensey, Sussex.
495 Kingdom of Wessex founded; King Cerdic dies; reign of Illan, Irish king who conducted raids on Britain (fl. 495–511)
500 Gildas born at Dumbarton.
504 Elevation and ordination of St. Dubricius.
510 death of Domingart, first Irish king of Dalriada.
515 Lull in the account of the Saxon conquest.
518 Account in the Annales Cambriae states "the Battle of Badon, in which Arthur and the Britons were the victors"
520 Reign of Gwynedd's Maelgwyn (fl. 520–551)
c. 525 Beowulf's victory over the dragon.
527 Justinian is emperor until 565
531 Comet reported.
539 The Annales Cambriae states "the strife of Camlann in which Arthur and Mordred perished"
540 Gildas writes his book recounting the twelve great battles later attributed to Arthur; Ida is king of Bernicia.
545 End of the reign of King Hoel of Armorica.
547 Saint David dies.
550 Anglo–Saxons push to settle east of Southhampton–Edinburgh line.
551 Maelgwyn of Gwynedd dies.
552 Cynric takes Salisbury and establishes Wessex.
559 King Owain kills Ida of Bernicia.
565 Ministry of Saint Columba on Iona.
c. 572 Gildas dies.
573 King Rydderch's ascension; ministry of Saint Kentigern.
574 Battle of Arthuret (Arthurydd, "Arthur's Head"); inauguration of King Aidan of Dalriada by Saint Columba.
584 Meeting of Saints Columba and Kentigern.
600 First reference to Arthur by name in the "Goddodin" (poem)
673 Bede's Ecclesiastical History of the British People is written. Like Gildas' works, it does not mention Arthur.
c. 828 The Historia Brittonum names Arthur and gives a listing of twelve battles he is said to have fought.
c. 1000 Culhwch and Olwen, widely considered to be the first Arthurian romance, is written.
1050–1071 Hordes of Seljuk Turks sweep over the Byzantine Empire and capture Jerusalem.
1095–1099 The First Crusade retakes Jerusalem.
c. 1100 The Life of St. Padarn refers to Arthur as a "tyrant."
1113 French monks travel to Bodmin, and a fight breaks out when a crippled man seeking healing insists that King Arthur is still alive.
1125 William of Malmesbury records that Arthur's grave is a mystery, and "ancient songs fable that he is still to come."
c. 1129–1151 Geoffrey of Monmouth's name appears on six different British charters.
c. 1130–1150 The Life of St. Gildas by Caradoc of Llangarfan records a dispute between Arthur and Gildas.
c. 1136 The History of the Kings of Britain is completed, causing Arthur's legend to spread all over the Continent.
1144 Edessa, first of the crusader–states is lost.
Eleanor of Acquitaine pledges thousands of her vassals to the Second Crusade, and shocks medieval society by joining it dressed in full battle armor.
1149 The Second Crusade is unsuccessful. Returning crusaders may bring back traditions of courtly love from the Arab world.
c. 1150 Geoffrey of Monmouth's second work, the Vita Merlini is completed.
c. 1150–1155 The Roman de Brut is written, adding the Round Table to the legend.
1160 Eleanor of Acquitaine's eldest daughter, Marie, is sent to the Avenay of Champagne to be educated. She later marries Henry, Count of Champagne, and becomes patroness to Chrétien de Troyes.
1170–1190 Chrétien makes his five contributions to the Arthurian Legend, recording the character of Lancelot for the first time.
1191 Monks from Glastonbury announce the discovery of King Arthur's tomb.
c. 1200 Robert de Boron writes his Joseph d'Arimathe and Prose Merlin, adding various details to the Grail legend, and various dimensions to Merlin's character.
c. 1215–1230 The Vulgate Cycle is written, containing elements of the loss of a sacred, religious symbol.
1278 The bones discovered at Glastonbury are transferred to separate caskets and moved to the great church at Glastonbury, by order of Edward I. Edward and his consort, Eleanor, visit the bones and put them on display before the high altar for all to see.
1485 William Caxton publishes Thomas Malory's Le Morte d'Arthur.
Henry Tudor defeats Richard III in battle. People all over Britain interpret this as a sign that Merlin's prophecy of the Welsh regaining control of the Island is coming true.
1539 Henry VIII seizes control of Glastunbury Abbey, destroying the tomb and bones discovered there centuries before.
1542 John Leland visits Somerset and learns the tale that Cadbury Hill was once King Arthur's "Camallatte."
1607 William Camden engraves the cross found in the tomb at Glastonbury.
c. 1800 Revival of interest in the Medieval Ages.
1819–1925 W. Gunn, J. A. Giles, W. W. Comfort, and others translate several Arthurian texts and romances into English, making them available to the general public.
1842 Alfred, Lord Tennyson publishes his first Arthurian poem, also titled Morte d'Arthur. Parallels are evident between Arthur and Prince Albert.
1850 Tennyson is named Poet Laureate.
1861 Prince Albert dies, prompting Tennyson to continue his work. Princess Alice expresses her wish that Tennyson idealize her father in verse.
1862 Tennyson meets Queen Victoria, and the two strike a lifelong friendship.
1868 William Forbes Skene produces the first modern translation of many of the poems of the Four Ancient Books of Wales.
1885 Tennyson completes the final poem which will comprise his Idylls of the King.
1888–1911 J. Gwenogvryn Evans transcribes several ancient Welsh manuscripts, including the Four Ancient Books of Wales into fascimile editions, making their original, Middle Welsh text widely–available to scholars.
1935 Excavations by Ralegh Radford uncover evidence of an ancient Celtic center of worship at Tintagel.
1938 T. H. White publishes The Sword in the Stone.
1939 Britain enters World War II. The devastation shapes the future books which will eventually become White's The Once and Future King.
1957–1984 Geoffrey Ashe, Leslie Alcock, and others publish a series of works which renew interest in the history of the Arthurian Legend.
1963 Walt Disney Pictures adapts White's The Sword in the Stone into the animated film.
Ralegh Radford finds evidence that monks did, indeed, discover a tomb at Glastonbury.
1965 The Camelot Research Committee is formed.
1966–1970 Excavations of Cadbury Hill promote interest in the Arthurian Legend.
1970–1983 Mary Stewart publishes her Merlin series.
In 1983, fires at Tintagel uncover evidence of a royal citadel and center of trade there.
1975 Monty Python and the Holy Grail is released to positive reviews.
1995 The film First Knight is released.
1998 Hallmark, in conjunction with NBC Studios, produces the Merlin miniseries starring Sam Neil and Isabella Rossellini.
2004 The film King Arthur is released, loosely based on the historical figure Lucius Artorius Castus.
2008–2012 The BBC series Merlin receives positive reviews.