c.2000 - Construction began on Stonehenge's inner ring of bluestones

55 - Julius Caesar's first invasion of Britain.

54 - Julius Caesar's second invasion of Britain.

AD
5 - Rome acknowledges Cymbeline, King of the Catuvellauni, as king of Britain

43 - Claudius' invasion of the island. Caratacus leads British resistance, but is finally defeated in 51.

51 - Caratacus, British general, is captured and taken to Rome

61 - Boudicca, queen of the Iceni, led uprising against the Roman occupiers, but is defeated and killed by the Roman governor, Suetonius Paulinus

63 - Joseph of Arimathea came to Glastonbury on the first Christian mission to Britain.

77 - The Roman conquest of Britain; Julius Agricola is imperial governor (to 84)

122 - Construction of Hadrian's Wall ordered along the northern frontier, for the purpose of hindering incursions of the aggressive tribes there into Britannia

133 - Julius Severus, governor of Britain, is sent to Palestine to crush the revolt

167 - At the request of King Lucius, the missionaries, Phagan and Deruvian,were said to have been sent by Pope Eleutherius to convert the Britons to Christianity. This is, perhaps, the most widely believed of the legends of the founding of Christianity in Britain.

197 - Clodius Albinus, governor of Britain, another claimant to the Imperial throne, is killed by Severus at the battle of Lyon

208 - Severus goes to defend Britain, and repairs Hadrian's Wall

209 - St. Alban, first British martyr, was killed for his faith in one of the few persecutions of Christians ever to take place on the island, during the governorship of Gaius Junius Faustinus Postumianus (there is controversy about the date of Alban's martyrdom. Some believe it occurred during the persecutions of Diocletian, in the next century, although we opt for the earlier dating).

c.270 - Beginning (highly uncertain dating) of the "Saxon Shore" fort system, a chain of coastal forts in the south and east of Britain, listed in a document known as "Notitia Dignitatum."

287 - Revolt by Carausius, commander of the Roman British fleet, who rules Britain as emperor until murdered by Allectus, a fellow rebel, in 293

303 - Diocletian orders a general persecution of the Christians

306 - Constantine (later to be known as "the Great") was proclaimed Emperor at York.

311 - Persecution of Christians in the Roman Empire ends.

312 - Constantine defeats and kills Maxentius at battle of Milvian Bridge; Constantine realizes Christian God may be a powerful ally and decides to attempt to co-opt him for his own purposes.

313 - Edict of Toleration proclaimed at Milan, in which Christianity is made legal throughout the empire.

314 - Three British bishops, for the first time, attend a continental church gathering, the Council of Arles.

324 - Constantine finally achieves full control over an undivided empire.

337 - Constantine received "Christian" baptism on his deathbed. Joint rule of Constantine's three sons: Constantine II (to 340); Constans (to 350); Constantius (to 361)

360's - Series of attacks on Britain from the north by the Picts, the Attacotti and the Irish (Scots), requiring the intervention of Roman generals leading special legions.

369 - Roman general Theodosius drives the Picts and Scots out of Roman Britain

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.