By Bruce Macfarlane, author of Notes on Arthurian Literature
From the mid-5th century south and eastern Britain began to receive Germanic settlements which generally coexisted with the British populations under treaties. Evidence is seen in Bede and the Anglo-Saxon Chronicle .
However, the beginning of the 6th century saw increased conflicts and migrations in Europe with pressure in the east from Slavic and Asiatic tribes pushing the Germanic tribes west . The Anglo-Saxon Chronicle begins to report wars and battles between the Britons and newly arrived Saxons, with a British victory at Baddon around 517 AD.
There have been various explanations for the invasions or migrations however the most probable driving force may have been a catastrophic change in the climate in the early 6th century. Evidence for this can be found in Romans, Celts and Saxons texts which record various plagues, solar eclipses and dark skies .
This table tries to compare events in Arthurian literature with external historical and astronomical events.
It includes a list of calculated dates of appearances of Halley’s Comet (53) and Solar/Lunar eclipses in Britain as calculated by NASA against such events recorded in medieval manuscripts.
Key to sources
BD: Bede,
NH: Nennius,
AC: Annales Cambrae,
ASC: Anglo-Saxon Chronical,
GLD: Gildas,
RW: Roger of Wendover
| 374 | Halley’s Comet (1P/374 E1): perihelion about 17 February. Recorded mainly from 4 March to 2 April; close approach about 0.09 AU. | |
| 375 | Valentinian II proclaimed western emperor; reigned 375–392. | |
| c. 378 | Probable birth of Germanus of Auxerre (died c. 448; both dates are approximate). | |
| 381 | BD/ASC: Maximus becomes emperor in Britain and crosses to Gaul. | |
| 383 | Magnus Maximus proclaimed emperor by troops in Britain; crosses to Gaul and defeats Gratian. | GM: Maximianus takes a large British force to Gaul. |
| 388 | Magnus Maximus defeated and executed at Aquileia. | |
| c. 389–390 | Philostorgius describes a new and strange light formed from bright globes and resembling a double-edged sword. Possibly a comet or atmospheric phenomenon. | |
| 401–402 | Troops associated with Stilicho were redeployed during the defence of Italy. The scale and precise date of any withdrawal from Britain remain uncertain. | |
| 402 | Honorius’s court established at Ravenna, which became the principal western imperial residence. | |
| 31 Dec. 406 | Vandals, Alans and Suebi cross the Rhine. The traditional date is 31 December 406; the claim that the river was frozen is uncertain. | |
| 407 | Constantine III proclaimed emperor in Britain. He crosses to Gaul with troops from Britain and establishes authority there. | GM: Constantine, brother of Aldroenus, is made king after Gracianus. Geoffrey’s literary Constantine is distinct from the historical Constantine III. |
| 409–410 | Breakdown of effective Roman imperial government in Britain. | BD: Following the capture of Rome, the Romans cease to rule Britain. Bede’s chronological summary places this under 409. |
| 410 | Famine and disease accompany the sieges and capture of Rome. Severe famine and warfare also affect parts of Hispania. Rome is captured by the Vusigoths | |
| 411 | Constantius, later Constantius III, forces Constantine III to surrender at Arles. Gerontius’s forces collapse; he flees to Hispania and dies during a mutiny. | |
| 19 July 418 | Total solar eclipse visible across parts of the Roman world. Philostorgius reports On 19 July AD 418, the Sun was so completely eclipsed that stars became visible. At about the same time, a bright cone-shaped object appeared and remained visible for more than four months, moving gradually from east to west and towards Ursa Major. | |
| 421 | Flavius Constantius becomes co-emperor Constantius III with Honorius; he dies after a reign of about seven months. | |
| 424–425 | Valentinian III made Caesar in 424 and western emperor in 425; reigned as Augustus until 455. | |
| 429 | First mission of Germanus of Auxerre to Britain, traditionally associated with the ‘Alleluia Victory’ against Picts and Saxons. | BD: Germanus leads the Britons in the Alleluia Victory. |
| c. 433–454 | Aetius is the dominant western Roman general and political figure. | |
| c. 441 | Chronica Gallica of 452 states that Britain, after many disasters, fell under Saxon control. Its chronology and meaning remain debated. | |
| 446 | Aetius holds his third consulship. | GLD: ‘To Aetius, thrice consul: the groans of the Britons.’ |
| c. 448 | Traditional date for the death of Germanus of Auxerre. | GLD: Pestilence affects Britain, but Gildas gives no exact year and does not associate it specifically with 448. |
| 449 | BD/ASC: Vortigern invites the Angles or Saxons, who arrive in three ships. GLD describes the proud tyrant inviting three keels but provides no year. | |
| 450 | Marcian becomes eastern Roman emperor; reigns 450–457. Chronicle of John of Nikiu:“And on the day of Marcian’s accession there was darkness over all the earth from the first hour of the day till the evening. And that darkness was like that which had been in the land of Egypt in the days of Moses.” | BD places Marcian’s accession and the traditional Saxon arrival under 449 |
| 451 | Halley’s Comet: recorded from June to August. Aetius and Theodoric I defeat Attila at the Battle of the Catalaunian Plains. | GLD describes widespread destruction by fire but supplies no date connecting the passage specifically with 451. Gallic Chronicle of 452 records that the northern sky became red “as though it were fire or blood”, with brighter lines resembling glowing spears. uncertain. |
| 454 | Aetius killed by Valentinian III. | |
| 455 | Total lunar eclipse on 19 January. Valentinian III assassinated by former followers of Aetius; Petronius Maximus seizes the western throne. | ASC: Hengest and Horsa fight Vortigern at Aylesford; Horsa is killed. |
| 457 | Leo I eastern emperor, 457–474. Majorian western emperor, 457–461. | ASC: Hengest and Æsc fight the Britons at Crayford, kill 4,000 men and drive the Britons from Kent to London. |
| 458 | Total solar eclipse. | HB: Germanus admonishes Vortigern. The narrative is undated; Germanus had died by about 448. |
| 461–465 | Libius Severus western emperor. | GM: Vortigern’s invitation of Hengest belongs to Geoffrey’s narrative chronology rather than to a dated historical event. |
| 465 | ASC: Hengest and Æsc fight the Welsh near Wippedfleet and kill twelve Welsh leaders; Wipped is killed on the English side. | |
| 467 | Anthemius becomes western emperor; reigns 467–472. | GM: The Britons appeal to Aurelius Ambrosius and Uther in Brittany; Ambrosius attacks Vortigern. |
| c. 469–471 | At the request of Anthemius, Riothamus, called ‘King of the Britons’ by Jordanes, brings 12,000 men by sea to Gaul and is defeated by Euric’s Visigoths before joining the Roman army. | |
| 472 | Eruption of Mount Vesuvius, 6 November AD 472: The major eruption known as the Pollena eruption devastated areas around Vesuvius and produced widespread ashfall. | |
| 473 | RW: Ambrosius defeats Saxons at Wipedesfleet | |
| 474 | 474-491 Zeno, Eastern Roman emperor | BD: Chronica Majora; In the reign of Zeno, the Britons, under the leadership of Ambrosius Aurelianus defeated them |
| 476 | Romulus Augustulus, last Western Roman emperor, deposed by Odoacer | |
| 480 | Zeno declares himself sole ruler of the Roman Empire | BD: 447 or 480 The Saxons were received by Vortigern, four hundred and forty-seven years after the passion of Christ, and, according to the tradition of our ancestors |
| 487 | RW: Ambrosius Aurelius slew a great multitude of Saxons | |
| 490 | RW: Ambrosius Aurelius besieges York with Merlin | |
| 494 | GLD: 494? Ambrosius Aurelius: Battle of Badon Hill- 44 years after the landing of the Saxons and Gildas’ birth BD: Ambrosius Aurelius. Under him till the year of the siege of Baddesdownhill, about forty-four years after their arrival in England | |
| 495 | ASC: Cerdic and Cynric his son came to Britain, fought with the Welsh the same day. Then Cerdic died and Cynric reigned for 26 years | |
| 497 | GLD: external wars stop but civil war continues RW: death of Aurelius Ambrosius and star on a fiery ball like a dragon | |
| 498 | Chronicle of Joshua the Stylite [January], we saw another sign in the exact south-west corner of the heavens, which resembled a spear. | GLD: 498? 5 Tyrants; Constantius of Dumnonia, Aurelius Caninus, Vortiporius, Cuneglasus, Maglocunus (Maelgwn) RW: Coronation of Uther Pendragon |
| 500 | HB: The Saxons were received by Vortigern, four hundred and forty-seven years after the passion of Christ, | |
| 501 | ASC: Beda & Bela slew a young Britain of high rank | |
| 507 | partial solar eclipse | |
| 508 | ASC: Cerdic and Cynric slew a British king whose name was Natanleod | |
| 514 | ASC: at Cerdic’s-ore. Stuff and Whitgar fought with the Britons, and put them to flight | |
| 516 | AC: Battle of Badon RW: Death of Uther and Arthur crowned King; a youth of 15 years | |
| 519 | ASC: Cerdic and Cynric established Wessex kingdom after battle of Cerdicesford | |
| 520 | HB: when Arthur penetrated to the hill of Badon. RW: Arthur at Badon | |
| 525 | Dionysius Exiguus introduced the Anno Domini dating system | |
| 527 | 527 -565 Justinian | RW: Justinian begins reign |
| 530 | 530 AD Chinese Annals of Wei (83) Halley’s Comet | ASC: 530 This year Cerdic and Cynric took the Isle of Wight, and slew many men. |
| 534 | ASC Cerdic died and son Cynric reigned for 26 yrs | |
| 536 | 536-546 Tree ring growth. Volcanic winter 536-7 Procopius “a grave portent”. whole year “the Sun sent forth his rays without his usual brilliance. Cassiodorus “The Sun lost its wonted light and seems of a bluish colour. We marvel to see no shadows of our bodies at noon” 536 partial solar eclipse | Irish annals – failure of bread. |
| 537 | 537 Siege of Rome (537–38) Gothic War. | AC: Camlann and the death of Arthur and Medraut. and there was plague in Britain and Ireland RW: Arthur Slays Lucas Roman Consul |
| 538 | 538 31/1 total lunar eclipse | ASC: 538 Eclipse of the sun. BD: Solar eclipse, 16 February |
| 539 | 539 sun was eclipsed | RW: sun was eclipsed |
| 540 | 540 20/6 total solar eclipse Rome 540 Zachariah of Mitylene said that “a great and terrible comet appeared in the sky at evening time for 100 days” about A.D. 540. | ASC: This year the sun was eclipsed RW: A great mortality in Constantinople BD: Solar eclipse, stars visible |
| 541 | 541 Plague of Justinian (541–542) | RW: a comet over Gaul. Rivers of blood fell from the clouds and great mortality just before the final battle between Arthur and Mordred RW: King Arthur died |
| 543 | RW: 2 sons of Mordred killed by Constantine | |
| 544 | 544 total solar eclipse | RW: a severe winter.. birds became tame. |
| 545 | RW: Constantine king of Britons died. Succeeded by nephew Aurelius Conan | |
| 546 | 536-546 Tree ring growth. Volcanic winter | |
| 547 | Polar ice-core sulphate and tree-ring evidence of volcanic eruption | AC: a great death. Maelgwn of Gwynedd died. Followed by yellow plague |
| 549 | Annals of Ulster: A great mortality in which these rested | |
| 552 | ASC: Cynric defeats Britons at Sarum | |
| 554 | RW: A severe winter and birds became tame | |
| 555 | RW: Lances in the northwest corner of the heavens | |
| 556 | ASC: Cynric defeats Britons at Beranbury | |
| 562 | 563: Gregory of Tours: the mountain Tauredunum collapsed near Lake Geneva, destroying settlements and causing a destructive wave across the lake | RW: A mountain collapsed near the Rhone destroying many villages 567: RW: fiery spears seen in the air. |
| 570 | AC: death of Gildas | |
| 571 | RW: completed one cycle of the Easter period 524 years after the crucifixion | |
| 573 | AC: The battle of Arfderydd between the sons of Eliffer and Gwenddolau son of Ceidio; in which battle Gwenddolau fell; Merlin went mad. | |
| 577 | ASC: Cuthwine and Ceawlin killed 3 British kings. Commail, Cordida, Farinmail at Dyrham | |
| 578 | RW: St Germanus died. Aurelius Conanus king of Britons died succeeded by Vortipore | |
| 580 | RW: fiery meteors. Ceawlin took Gloucester, Cirencester and Bath AC: Conversion of Constantine BD: Byzantine Emperor Maurice Tiberius dies | |
| 582 | Death of Tiberius II Constantine, Eastern Roman emperor from 578 to 582. | |
| 583 | :Gregory of Tours: chronicles immense, unseasonal flooding across Europe. Seine and Marne rivers in Paris rose so high that boats frequently shipwrecked. | |
| 584 | RW: Tiberius died | |
| 585 | October AD 585: Gregory of Tours records repeated nocturnal displays over Gaul consisting of bright rays in the northern sky and blood-red cloud-like forms. The direction, colour and movement described are consistent with an intense auroral display, | |
| 590 | Roman Plague: Flood and plague at Rome: Following severe flooding of the Tiber, Rome suffered an epidemic described by Gregory of Tours as an inguinal or groin plague. | 591. RW: Destruction and pestilence in Italy |
| 592 | total solar eclipse Constantinople | AC: Augustine converts English |
| 596 | RW: Augustine sent to Britain | |
| 601 | Apocalyptic warning attributed to Pope Gregory I who warns of “changes of air”, storms, wars, famines, plagues, earthquakes and “terrors from heaven | BD: many things are at hand which were not before, viz. changes of air, and terrors from heaven, and tempests out of the order of the seasons, wars, famines, plagues, earthquakes in several places |
| 604 | Pope Gregory dies | |
| 607 | Halley’s Comet Seen for over 100 days in China. | |
| 626 | AC: Edwin baptised | |
| 639 | 639 total solar eclipse | RW: Cerdic first king of Saxons dies |
| 661 | 661 partial solar eclipse | |
| 664 | 664 total solar eclipse 664 Synod of Whitby | ASC: This year the sun was eclipsed, on the eleventh of May; there was a great plague in the island Britain BD: there happened an eclipse of the sun, on the third of May. In the same year, a sudden pestilence depopulated of men. |
| 665 | AC: The first celebration of Easter among the Saxons. The second battle of Badon. Morgan dies | |
| 676 | 676-678 Great Comet X/676 P1: A brilliant, long-tailed comet was recorded in East Asian, Middle Eastern and European sources. | AC: “A star of marvellous magnitude was seen shining throughout the whole world.” BD: In August 678 “a star, called a comet” appeared and continued for three months; Wilfrid was expelled from his see. ASC: “The comet-star appeared in August and shone like a sunbeam every morning for three months.” RW: A comet appeared and shone for three months.BD: a comet appeared, and Bishop Wilfred driven from his See. |
| 680 | 680 Roman Plague. Ref: Paul the Deacon and in the [Liber Pontificalis] during the tenure of Pope Agatho. | |
| 682 | AC: A great plague in Britain, in which Cadwaladr son of Cadwallon dies | |
| 684 | 684 AD Chinese Annals of Tang (83) Halley’s Comet | AC: A plague was in Ireland |
| 686 | 686 eclipse of the moon | RW: eclipse of the moon |
| 687 | 687 Plague in Egypt | RW: a terrible pestilence also in Rome |
| 689 | Possible Saharan dessert dust storm ? | AC: The rain turned to blood in Britain, and in Ireland milk and butter turned sour |
| 698 | partial solar eclipse | |
| 729 | ASC: Anglo-Saxon Chronicle ..this year a star appeared and St. Egbert died | |
| 733 | 733 partial solar eclipse | ASC: the sun was eclipsed; |
| 734 | 734 total lunar eclipse | RW: 7 Bede died RW: Moon suffused with blood ASC:. This year was the moon as if covered with blood; |
| 735 | 735 Death of Bede | |
| 758 | 758 total solar eclipse | |
| 760 | 760AD Chinese Annals of Tang (83) Halley’s Comet 760 eclipse of the moon | RW: eclipse of the moon |
| 764 | 764 partial solar eclipse | |
| 774 | 774–775 Carbon-14 Spike: Possible Solar flare | RW: This year also appeared in the heavens a red crucifix, after sunset; the Mercians and the men of Kent fought at Otford; and wonderful serpents were seen in the land of the South-Saxons. |
| 793 | ASC: This year came dreadful fore-warnings over the land of the Northumbrians, terrifying the people most woefully: These tremendous tokens were soon followed by a great famine immense sheets of light rushing through the air, and whirlwinds, and fiery, dragons flying across the firmament. | |
| 795 | ASC: This year was the moon eclipsed, between cock-crowing and dawn, on the fifth day before the calends of April | |
| 796 | RW: Small globes seen around the sun. | |
| 800 | ASC. This year was the moon eclipsed, at eight in the evening [or second hour of the night], on the seventeenth day before the calends of February | |
| 806 | ASC: here the moon grew dark on 1 September | |
| 807 | ASC. This year was the sun eclipsed, | |
| 818 | 818 partial solar eclipse | |
| 827 | ASC: This year was the moon eclipsed | |
| 837 | 837 February 6 Halley’s Comet Annals of Tang | |
| 838 | RW: a great terrible plague | |
| 848 | RW: eclipse of the sun | |
| 852 | 852 partial solar eclipse | |
| 878 | 878 total solar eclipse | |
| 879 | ASC the sun goes dark | |
| 885 | 885 total solar eclipse | ASC: the sun grew dark |
| 891 | 891 Comet observed, China | RW: a star appeared… some men say that in English it may be termed “hairy star”; for that there standeth off from it a long gleam of light |
| 905 | 905 Comet observed, China | ASC: Here a comet appeared. |
| 906 | RW: a comet appeared for half a year. | |
| 912 | (83) Halley’s Comet 912 18 July, 912 Chinese Annals of the Five Dynasties . | 912 Annals of Ulster (a chronicle of medieval Ireland) notes in its final entry for AD 912: “A dark and rainy year. A comet appeared |
| 975 | ASC: and this year Edward, Edgar’s son, succeeded to the kingdom; and then soon, in the same year, during harvest, appeared “comet” the star; RW: A comet appeared followed by dreadful famine. | |
| 987 | RW: 2 Plagues. One of people, the other of animals | |
| 989 | 989 AD Chinese Annals of Song Halley’s Comet | |
| 995 | ASC: a comet that is haired | |
| 1066 | 1066 Halley’s Comet | ASC: AD 1066 ASC. Then was over all England such a token seen as no man ever saw before. Some men said that it was the comet-star, which others denominate the long-haired star. It appeared first on the eve called “Litania major” that is, on the eighth before the calends of May; and so shone all the week RW: Harold’s death predicted by large comet of bloody colour with a long train |