33-37 AD - Christianity is said, by Gildas, to have come to Britain sometime during the latter part of the reign of Tiberius Caesar who ruled from 14-37 AD:
Meanwhile these islands, stiff with cold and frost, and in a distant region of the world, remote from the visible sun, received the beams of light, that is, the holy precepts of Christ, the true Sun, showing to the whole world his splendour, not only from the temporal firmament, but from the height of heaven, which surpasses every thing temporal, at the latter part, as we know, of the reign of Tiberius Caesar, by whom his religion was propagated without impediment, and death threatened to those who interfered with Its professors.
And, since Joseph of Arimathea is often credited with being the one who first introduced Christianity to Britain, then it is not too far-fetched to assume that the two must've arrived together. Christ is believed to have been crucified in 32 AD and allowing a year as a minimum time to organize and launch a mission, then Joseph could have come to Britain, at the very earliest, in 33 AD or at the latest, 37 AD. This assumes, of course, that Gildas can be trusted on this point. We report this not to suggest that it is true, merely to include it in the record for completeness.
63 - Joseph of Arimathea came to Glastonbury on the first Christian mission to Britain. Legend says that he brought with him the Holy Grail, which was either a cup/bowl or two "cruets" thought to contain the blood and sweat of the crucified Christ.
184 - Lucius Artorius Castus, commander of a detachment of Sarmatian conscripts stationed in Britain, led his troops to Gaul to quell a rebellion. This is the first appearance of the name, Artorius, in history and some believe that this Roman military man is the original, or basis, for the Arthurian legend. The theory says that Castus' exploits in Gaul, at the head of a contingent of mounted troops, are the basis for later, similar traditions about "King Arthur," and, further, that the name "Artorius" became a title, or honorific, which was ascribed to a famous warrior in the fifth century.
383 - Magnus Maximus (Macsen Wledig), a Spaniard, was proclaimed Emperor in Britain by the island's Roman garrison. With an army of British volunteers, he quickly conquered Gaul, Spain and Italy.
388 - Maximus occupied Rome itself. Theodosius, the eastern Emperor, defeated him in battle and beheaded him in July, 388, with many of the remnant of Maximus' troops settling in Armorica. The net result to Britain was the loss of many valuable troops needed for the island's defense (the "first migration").
395 - Theodosius, the last emperor to rule an undivided empire, died, leaving his one son, Arcadius, emperor in the East and his other son, the young Honorius, emperor in the West. At this point the office of Roman Emperor changed from a position of absolute power to one of being merely a head of state.
396 - The Roman general, Stilicho, acting as regent in the western empire during Honorius' minority, reorganized British defenses decimated by the Magnus Maximus debacle. Began transfer of military authority from Roman commanders to local British chieftains.
397 - The Roman commander, Stilicho, comes to Britain and repels an attack by Picts, Irish and Saxons.
402 - Events on the continent force Stilicho to recall one of the two British legions to assist with the defense of Italy against Alaric and the Visigoths. The recalled legion, known as the Sixth Victrix, was said by Claudian (in "De Bello Gallico," 416) to be "that legion which is stretched before the remoter Britons, which curbs the Scot, and gazes on the tattoo-marks on the pale face of the dying Pict." The barbarians were defeated, this time, at battle of Pollentia.
403 - Victricius, Bishop of Rouen, visited Britain for the purpose of bringing peace to the island's clergy, who were in the midst of a dispute, possibly over the Pelagian heresy.
405 - The British troops, which had been recalled to assist Stilicho, were never returned to Britain as they had to stay in Italy to fight off another, deeper penetration by the barbarian chieftain, Radagaisus.
406 - In early January, 406, a combined barbarian force (Suevi, Alans, Vandals & Burgundians) swept into central Gaul, severing contact between Rome and Britain. In autumn 406, the remaining Roman army in Britain decided to mutiny. One Marcus was proclaimed emperor in Britain, but was immediately assassinated.
407 - In place of the assassinated Marcus, Gratian was elevated "to the purple," but lasted only four months. Constantine III was hailed as the new emperor by Roman garrison in Britian. He proceeded to follow the example of Magnus Maximus by withdrawing the remaining Roman legion, the Second Augusta, and crossing over into Gaul to rally support for his cause. Constantine's departure could be what Nennius called "the end of the Roman Empire in Britain. . ."
408 - With both Roman legions withdrawn, Britain endures devastating attacks by the Picts, Scots and Saxons.
409 - Prosper, in his chronicle, says, "in the fifteenth year of Honorius and Arcadius (409), on account of the languishing state of the Romans, the strength of the Britons was brought to a desperate pass." Under enormous pressure, Britons take matters into their own hands, expelling weak Roman officials and fighting for themselves.
410 - Britain gains "independence" from Rome. The Goths, under Alaric, sack Rome.
413 - Pelagian heresy said to have begun, by Prosper (Tiro) of Aquitaine in his "Chronicle."
420-30 - Pelagian heresy outlawed in Rome (418), but in Britain, enjoys much support from "pro-Celtic" faction. Traditionalists (pro-Romans) support Roman church. During this time, according to Prosper, Britain is ruled by petty "tyrants."
429 - At the request of Palladius, a British deacon, Pope Celestine I dispatches bishops Germanus of Auxerre and Lupus of Troyes to Britain to combat Pelagian heresy. While in Britain, Germanus, a former military man, leads Britons to "Hallelujah" victory in Wales.
c.438 - Probable birth of Ambrosius Aurelianus, scion of the leading Romano-British family on the island.
c.440-50 - Period of civil war and famine in Britain, caused by ruling council's weakness and inability to deal with Pictish invasions; situation aggravated by tensions between Pelagian/Roman factions. Vacated towns and cities in ruin. Migration of pro-Roman citizens toward west. Country beginning to be divided, geographically, along factional lines.
c.441 - Gallic Chronicle records, prematurely, that "Britain, abandoned by the Romans, passed into the power of the Saxons."
c.445 - Vortigern comes to power in Britain.
446 - Britons (probably the pro-Roman party) appeal to Aetius, Roman governor of Gaul, for military assistance in their struggle against the Picts and the Irish (Scots). No help could be sent, at this time, as Aetius had his hands full with Attila the Hun.
c.446 - Vortigern authorizes the use of Saxon mercenaries, known as foederati, for the defense of the northern parts against barbarian attack. To guard against further Irish incursions, Cunedda and his sons are moved from Manau Gododdin in northern Britain to northwest Wales.
447 - Second visit of St. Germanus (this time accompanied by Severus, Bishop of Trier) to Britain. Was this visit spiritually motivated, to combat a revived Pelagian threat or was Germanus sent in Aetius' stead, to do whatever he could to help the desperate Britons?
c.447 - Britons, aroused to heroic effort, "inflicted a massacre" on their enemies, the Picts and Irish, and were left in peace, for a brief time. Could this heroic effort have been led, again, by St. Germanus?
c.448 - Death of St. Germanus in Ravenna. Civil war and plague ravage Britain.
c.450 - In the first year of Marcian and Valentinian, Hengest arrives on shores of Britain with "3 keels" of warriors, and are welcomed by Vortigern. This event is known in Latin as the "adventus Saxonum," the coming of the Saxons.
c.452 - Increasing Saxon settlement in Britain. Hengest invites his son, Octha, from Germany with "16 keels" of warriors, who occupy the northern lands, to defend against the Picts. Picts never heard from, again.
c.453 - Increasing Saxon unrest. Raids on British towns and cities becoming more frequent.
c.456 - Geoffrey of Monmouth tells us of a probably fictitious, but entirely believable event in which Saxons massacre 300 leading British noblemen at phony "peace" conference. Ambrosius' father, possibly the leader of the pro-Roman faction, may have been killed either during the Saxon uprising or this massacre.
c.457 - Death of Vortigern. Vitalinus (Guitolinus) new leader of pro-Celtic Pelagian faction. Battle of Aylesford (Kent) in which Ambrosius, along with sons of Vortigern, Vortimer and Cateyrn, defeat Hengest for the first time.
c.458 - Saxon uprising in full-swing. Hengest finally conquers Kent, in southeastern Britain.
c.458-60 - Full-scale migration of British aristocrats and city-dwellers across the English Channel to Brittany, in northwestern Gaul (the "second migration"). British contingent led by Riothamus (perhaps a title, not a name), thought by some to be the original figure behind the legends of Arthur.
c.460-70 - Ambrosius Aurelianus takes full control of pro-Roman faction and British resistance effort; leads Britons in years of back-and-forth fighting with Saxons. British strategy seems to have been to allow Saxon landings and to then contain them, there.
c.465 - Arthur probably born around this time.
c.466 - Battle of Wippedesfleot, in which Saxons defeat Britons, but with great slaughter on both sides. Mutual "disgust and sorrow" results in a respite from fighting "for a long time."
c.466-73 - Period of minimal Saxon activity. Refortification of ancient hillforts and construction of the Wansdyke possibly takes place during this time.
c.469 - Roman emperor, Anthemius, appeals to Britons for military help against the Visigoths. Reliable accounts by Sidonius Apolonaris and Jordanes name the leader of the 12,000 man British force, Riothamus. The bulk of the British force was wiped out in battle against Euric, the Visigothic king, and the survivors, including Riothamus, vanished and were never heard from, again.
c.470 - Battle of Wallop (Hampshire) where Ambrosius defeats Vitalinus, head of the opposing faction. Ambrosius assumes High-kingship of Britain.
473 - Men of Kent, under Hengest, move westward, driving Britons back before them "as one flees fire."
477 - Saxon chieftain, Aelle, lands on Sussex coast with his sons. Britons engage him upon landing but his superior force drives them into the forest (Weald). Over next nine years, Saxon coastal holdings are gradually expanded in Sussex.
c.480 - "Vita Germani," the Life of St. Germanus, written by a continental biographer, Constantius.
c.485-96 - Period of Arthur's "twelve battles" during which he gains reputation for invincibility.
486 - Aelle and his sons overreach their normal territory and are engaged by Britons at battle of Mercredesburne. Battle is bloody, but indecisive, and ends with both sides pledging friendship.
c.490 - Hengest dies. His son, Aesc, takes over and rules for 34 years.
c.495 - Cerdic and Cynric, his son, land somewhere on the south coast, probably near the Hampshire-Dorset border.
c.496 - Britons, under overall command of Ambrosius and battlefield command of the "war leader" Arthur, defeat Saxons at the Siege of Mount Badon.
c.496-550 - Following the victory at Mt. 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 next fifty years, making Britain ripe for final Saxon "picking."
c.501 - The Battle of Llongborth (probably Portsmouth), where a great British chieftain, Geraint, King of Dumnonia, was killed. Arthur is mentioned in a Welsh poem commemorating the battle.
508 - Cerdic begins to move inland and defeats British king Natanleod near present-day Southampton.
c.515 - Death of Aelle. Kingdom of Sussex passed to his son, Cissa and his descendents, but over time, diminished into insignificance.
519 - Kingdom of the West Saxons (Wessex) founded with Cerdic its first ruler.
c.530-40 - Mass migration of Celtic monks to Brittany (the "third migration").
534 - Death of Cerdic. Cynric takes kingship of Wessex.
c.540 - Probable writing of Gildas' "De Excidio Britanniae."
c.542 - Battle of Camlann, according to Annales Cambriae. Death (or unspecified other demise) of Arthur (according to Geoffrey of Monmouth).
c.547 - "Yellow" Plague hits British territories, causing many deaths. Ireland also affected. Saxons, for whatever reason, are unaffected by it.
c.570 - Probable death of Gildas.
c.600 - Welsh bard, Aneirin, writes poem, Y Gododdin, alluding to Arthur's prowess as a warrior.
c.600-700 - Original Welsh triads probably composed; only later, medieval collections survive.
c.830 - Nennius compiles Historia Brittonum.
c.890 - Compilation of Anglo Saxon Chronicle is begun, perhaps at the direction of Alfred the Great.
c.970 - Annales Cambriae compiled.
c.1019 - Earliest possible date of composition for the Legend of St. Goeznovius, a Breton legend, which, in its preface, mentions Arthur and calls him the King of the Britons. Date is disputed as some scholars think this legend should be dated later than Geoffrey of Monmouth.
c.1090 - Professional hagiographers, such as Caradoc of Llancarfan, Lifris and others, write various saints lives, some (St. Gildas, St. Padarn, St. Cadog, St. Iltud) include mentions of Arthur and his exploits.