Climatic and Astronomical Events from the 4th to 11th Century

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




Historical Events


374 16 Feb 374   Halley’s Comet. This event remained above magnitude 0 for 10 weeks  
375 375-392 Valentinian II  
378 378 – 448 St Germanus of Auxerre  
381 ASC: This year Maximus the Caesar came to the empire. He was born in the land of Britain
383 Magnus Maximus appointed governor of Britain: takes large proportion of British to Gaul & defeats Gratian NH: Maximian took 30,000 soldiers to Gaul
388 Maximus killed at Aquileia  
391 ‘Bright globes’ at night merged into a ‘sword’. ‘Time of Theodosius’. Possibly comet of 390.  
399 Stilicho save Britain  
407 Barbarians cross frozen Rhine

407-411 Constantine III emperor in Britain. Constantine II in Geofrey’s Historia appointed by Gracianus (Gratian?) soldiers of Maximus

409 Britain devastated by Saxons  
410 Plague & Famine in Rome – Honorius  
411 Constantius III defeated Gerontius, the general of usurper Maximus, and Constantine III,  
421 Constantius III co-emperor of the Western Empire with Honorius for 7 months BD: 420 Then the Romans ceased to rule in Britain, almost 470 years after Caius Julius Caesar entered the island
424 424-450 Valentinian III BD: 426-447 a severe plague fell upon that corrupt generation
433 433-454 Flavius Aetius ASC: Appeal by Britons for help against Picts and Irish


GLD: To Aetius, now consul for the third time: the groans of the Britains
BD: King Vortigern to call over to their aid, from the parts beyond the sea, the Saxon nation
446 BD: 446. To Ætius, thrice Consul, the groans of the Britons.
447 RW: Scots and Picts rise up against Vortigern
448 378 – 448 St Germanus of Auxerre GLD: a pestilential disease mortally affected

RW: Germanus defeats Scots and Picts


RW:  Scots and Picts rise up against Vortigern
449 449 Marcian III made emperor with Valentinian GLD:? Proud tyrant invites 3 keels of saxons


BD: Martian & Valentinian ruled the empire seven years. Then Saxons, invited by the aforesaid king, arrived in three long ships.


RW: Vortigern invites Hengest & Horsa to Britain – 3 keels


ASC: Vortigern invites Hengest & Horsa to Britain
451 Halley’s Comet

451AD Annals of Sung Halley’s Comet

451 A.D. Comet. Hydatius Bishop of Aquae Flaviae. This appearance coincided with Attila the Huns fall

451 Aetius and Theodoric I defeats Attila

GLD:? The country ravaged by fire and all the towns destroyed


BD: Arrival of Saxons. Hengest & Horsa invited by Vortigren


NH: Constantine, brother of Aldroen. Sons Constans, Uther, Aurelius Ambrosius


455 455 19/1 total lunar eclipse ASC: Hengest & Horsa fights Vortigern at Aylesford


NH:? Vortgern kills Constans and becomes king

NH:? Hengest & Horsa invited by Vortigren

  455 Aetius & Valentinium III killed by Petronius Maximus  
457 Leo I 457-474 ASC: Hengest kills 4000 Britons
458 total solar eclipse NH:? St Gerrmanus admonishes Vortigern
460 460-465 Emperor Libius Severus RW: Vortigern invites Hengest to Britain
464 464 partial solar eclipse RW: Britons send message for help to Aurelius Ambrosius and his brother Uther in Brittany
466 ASC: Hengest defeats Welsh near Wipped’s Creek

RW: Ambrosius attacks Vortigern who has killed his father and brother

467 467-472 Emperor Anthemius recruited the Breton Riothamus living in Armorica to fight Euricus  
473 RW: Ambrosius defeats Saxons at Wipedesfleet
474 474-491 Zeno last western emperor BD: Chronica Majora; In the reign of Zeno, the Britons, under the leadership of Ambrosius Aurelianus defeated them
480 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 Baddon 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 fortyfour 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 GLD: 498? 5 Tyrants; Constantius of Dumnonia, Aurelius Caninus, Vortiporius, Cuneglasus, Maglocunus (Maelgwn)


RW: Coronation of Uther Pendragon
500   NH:  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 Wihtgar fought with the Britons, and put them to flight
516   ANC: Battle of Baddon


RW: Death of Uther and Arthur crowned King; a youth of 15 years
519   ASC: Cerdic & Cynric establishes Wessex kingdom after battle of Cerdicesford
520   NH: when Arthur penetrated to the hill of Badon.

RW: Arthur at Baddon

525 Anno Domini starts for dating  
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  
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 lasting all day
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
541 541 Plague of Justinian (541–542) RW: a comet over Gaul and great mortality just before the final battle between Arthur and Mordred
543 RW: 2 sons of Mordred killed by Constantine
544 544 total solar eclipse  
545 RW: Constantine king of Britons died. Succeeded by nephew Aurelius Conan
546 536-546 Tree ring growth. Volcanic winter  
547 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
556   ASC: Cynric defeats Britons at Beranbury
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:  Cuthwin & Cuthu kill 3 British kings. Commail, Cordida, Farinmail at Dyrham
578   RW:  St Germanus died. Aurelus Conanus king of Britons died succeeded by Vortipore
580   RW: firey meteors. Ceaulin took Gloucester, Cirencester and Bath


AC: Conversion of Constantine


BD:  Maurice
584   RW:  Tiberius died
590 Roman Plague: Death of Pope Pellagius II  
592 total solar eclipse Constantinople AC: Augustine converts English
601 AC: Pope Greogory dies


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 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 In the same year, a sudden pestilence depopulated of men.
665 ANC: The first celebration of Easter among the Saxons. The second battle   of Badon. Morgan dies
676 676-677 Japan, China, Italy – Comet AC: A star of marvelous brightness was seen shining throughout the whole world


RW: Comet appeared and shone for 3 months


ASC: here the star comet appeared and shone for 3 months


BD: a comet appeared and Bishop Wifred driven from his See
680 680 Roman Plague  
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 ANC: 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: Possile 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
800   ASC.  This year was the moon eclipsed, at eight in the
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.
912 912 18 July, 912 Chinese Annals of the Five Dynasties (83) Halley’s Comet  
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.  


ASC:  and this year Edward, Edgar’s son, succeeded to the kingdom; and then soon, in the same year, during harvest, appeared “cometa” the star;


RW: A comet appeared followed by dreadful famine.
989 989 AD Chinese Annals of Sund 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-hair’d star.  It appeared first on the eve called “Litania major” that is, on the eighth before the calends off May; and so shone all the week


RW: Harold’s death predicted by large comet of bloody colour with a long train

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