c. 500 BC
The Celts appear on the historical scene, first mentioned by the Greek Herodotus, already having spread over much of Alpine Europe, in areas immediately to the north, in central France and in parts of Spain. This period is associated with the Hallstatt culture. Trade with Mediterranean countries especially the Greek colony of Massalia (Marseilles).

c. 500-400 BC
The La Tène culture arises in an area stretching from eastern France to Bohemia.

c. 400 BC
The La Tène Celts erupt over the Alps and invade northern Italy, settling there. The Romans called these settlements Gallia Cisalpina (Gaul this side of the Alps).

c. 390 BC
These Gauls sack a young Rome but withdraw after a ransom has been paid. They fail to capture Capitol Hill. In 367 BC, Celts besiege Rome again.

c. 400-300 BC
Other Celts migrate through the Balkans and in 279 BC sack Delphi in Greece. The Greeks called these people Keltoi or Galatae. Some go further and carve out a kingdom in Asia Minor (Turkey) called Galatia.

c. 500-300 BC
La Tène culture also emerges in northern France and the British Isles (especially decorated metalwork). This might reflect the migration of Celts north and west or the spread of a fashion.

349 BC
The Roman army defeats a Celtic army for the first time at Apulia in Italy.

340 BC
Roman commanders are forbidden to settle warfare by single combat with Celtic Chieftains.

335-334 BC
Alexander the Great meets Celtic Chieftains on the Danube.

c. 225-100 BC
From the major Celtic loss at the Battle of Telamon, Celtic lands come under pressure from the Germanic tribes to the north, and the spread of Rome. Gallia Cisalpina and southern Gaul are conquered; the Iberian Peninsula falls by degrees.

93 BC
Celts of the Iberian Peninsula submit to the 'pax Romana'. But revolt continue till around the millennium.

c. 90-80 BC
The Galatian kingdom is crushed by the Romans.

58-51 BC
Caesar conquers 'all of Gaul'. In 52 BC Vercingetorix revolts, but is eventually defeated at Alesia. Vercingetorix is beheaded publicly in Rome in 46 BC.

55-54 BC
Caesar raids Britain; does not set up permanent occupation.

7 BC
Strabo speaks of Ireland in his Geography.

43 AD
Claudius orders invasion of Britain. By 85 AD Rome had conquered as far north as the Highlands of Caledonia (Scotland). Occupation of Caledonia could not be maintained past c. 200 AD, due to 'the fierceness of the Picts'.

82 AD
Agricola, Governor of Britain, shelves plan to invade Ireland via northern Britain.

c. 370-600 AD
Scotti (Irish) raid and settle in the west of Caledonia, and parts of Wales and Cornwall, and the Isle of Man.

c. 400-600 AD
The Irish are Christianised. Patricius (St Patrick) - a Briton - returns to Ireland in 432 AD as bishop. Ireland becomes the centre of a new Celtic Church, and one of the most 'civilised' and Christianised parts of western Europe. Many monasteries (monastic cities) are founded.

c. 410-476 AD
Collapse of the Roman Empire in the west. Western Roman lands are over-run by Germanic peoples. The name Gaul disappears. This process is slower in Britain.

c. 420 AD
The Ui Neill clan are ascendant in Ireland.

c. 450 AD
Ireland's civil law, the Senchus Mor, is reputedly codified. Now claimed as the oldest surviving codified law system in western Europe.

c. 450-600 AD
Angles, Saxons and Jutes invade and settle the east of Britain. The west (Wales and Cornwall) and north (Caledonia, Cumbria, Strathclyde) sees the survival of Celtic culture, language and social structure. In this period, Britons migrate to Armorica (Brittany).

c. 470 AD
Traditional date for Fergus Mor Mac Eirc's crossing from Ulster to Britain and the formation of the kingdom of Dal Riada in Kintyre. This is the progenitor of the Kingdom of Scotland.

516 or 518 AD
The Battle of Mount Badon, perhaps led by King Arthur.

563 AD
The monastery of Iona (off the west coast of Scotland) is founded by St Columba from Ireland.

634 AD
St Aidan from Iona establishes a monastery at Lindisfarne.

664 AD
Council of Whitby in Northumbria, presided over by King Oswy, settles on the Roman instead of the Celtic Christian date for Easter.

c. 600-800 AD
The Golden Age of Irish literature and scholarship.

710 AD
Geraint, last recorded King of Dumnonia, defeated in battle with Ine of Wessex.

768 AD
Wales adopts the Roman Easter.

c. 780-900 AD
The Vikings begin raiding western Europe (and the east for that matter). 793 AD Vikings sack Lindisfarne. 794 AD Vikings raid Iona, and burn it again in 802 AD.

c. 785 AD
Offa of Mercia builds a dyke along the border with Wales.

795 AD
The Vikings raid near Dublin. The Norse kingdom of Dublin is established by Thorgil in 841 AD.

c. 810 AD
The Book of Kells is completed; begun on Iona and relocated.

838 AD
Celts of Cornwall/Dumnonia defeated by Egbert of Wessex.

839 AD
Viking victory over the Picts; King Eoganan slain in battle.

843 AD
The Scots of Dalriada under Kenneth mac Alpin seize the Pictish throne, unifying a large part of present day Scotland: the Kingdom of Alba.

844-78 AD
Rhodri Mawr (the Great) is King of Gwynedd and overlord of most of Wales. Defeats a Viking advance. His bloodline becomes 'sacred'.

846 AD
Charles the Bald of Frankia recognises the independence of Brittany under treaty.

851 AD
Brittany becomes a kingdom.

878 AD
England narrowly escapes complete overthrow by Vikings; King Alfred of Wessex alone survives and gradually wins back.

c. 885-893 AD
Lesser Kingdoms of southern Wales accept Alfred of Wessex as overlord, Gwynedd and Seisyllwg follow.

c. 900 AD
The kingdom of Alba, under Constantine II, annexes British Celtic kingdoms of Strathclyde and Cumbria.

911 AD
Rollo the Viking is granted land by the Frankish king, which becomes Normandy.

c. 915-50 AD
Hywel ap Cadell (Hywel Dda - the Good) overlord of most of Wales, holds a parliament to codify customary Welsh law.

937 AD
The last alliance of Celts - Alba, Strathclyde, Dublin Vikings - to drive out the Anglo-Saxons is defeated by King Aethelstan at Brunanburh.

1014 AD
The Irish, under Brian Boru, defeat the Vikings at Clontarf.

1039-63 AD
Reign of Gruffydd ap Llywelyn of Gwynedd, only known overlord of all Wales (and then only from 1057-63).

1066 AD
William, Duke of Normandy, defeats Harold II, and takes the English throne. This heralds the beginning of mass takeover by the Norman descendants.

1071 AD
William invades Scotland; Malcolm III pays him homage.

1169 AD
Anglo-Normans invade east of Ireland; the Pale is established.

1282 AD
The last native Prince of Wales, Llywelyn ap Gruffydd (The Last) is killed. Edward I (Longshanks) imposes his son as 'Prince of Wales' and Wales loses independence.

1286 AD
Alexander III of Scotland dies without a male heir; his grand-daughter Margaret (Maid of Norway) dies soon after on route from Norway.

1296 AD
Annexation of Scotland by Edward I. He invades and steals the 'Stone of Scone'.

1297 AD
The emergence of William Wallace - defeats English at Stirling Bridge and becomes Guardian of Scotland. Defeated at Falkirk in 1288, he resigns the Guardianship. He is betrayed and 'hung, drawn and quartered' in 1305 AD.

1314 AD
Robert Bruce defeats Edward II at Battle of Bannockburn, to become Robert I of Scotland.

1366 AD
Statutes of Kilkenny, which were to limit interaction between English and Irish.

1532 AD
Brittany is defeated and subsumed within France.

1536-42 AD
The Acts of Union (the Statutes of Wales) between Wales and England. Wales is now part of England.

1550-1600 AD
Ireland falls fully under English rule (reign of Elizabeth I).

1603 AD
James VI of Scotland becomes James I of England.

1607 AD
'Flight of the Earls' from Ulster; much of their land reverts to the English Crown. 1608 onwards: 'plantations' begin in Ireland.

1690 AD
William of Orange (William III) defeats James II at the Battle of the Boyne.

1692 AD
The Massacre of Glencoe; Clan Campbell kills members of Clan MacDonald.

1695 AD
First Penal Laws enacted against Catholics in Ireland, limiting property and political rights.

1707 AD
Scotland formally unified with England to create the United Kingdom; Scotland's parliament abolished.

1715 AD
First Jacobite Rising, for James Francis Stuart the 'Old Pretender', defeated at Battle of Sheriffmuir.

1745 AD
The second Jacobite Rebellion of Charles Edward Stuart the 'Young Pretender', culminating in his defeat at Culloden in 1746 AD. Highland clan society is effectively destroyed in the aftermath.

1801 AD
Ireland is incorporated into the United Kingdom; the Act of Union.

1750-1900 AD
Severe economic difficulties in Celtic regions of Britain. Highland clearances (1785-1854). This period also saw the steep decline in the number of people speaking Celtic languages. This decline has continued into the 20th Century.

1843 AD
Daniel O'Connell's 'Monster Meetings' for the repeal of the Act of Union.

1845-49 AD
The potato famine in Ireland. Millions die or migrate to America, Australia, New Zealand, England.

1922 AD
The Irish Free State is formed, with the Anglo-Irish Treaty agreed to in December 1921. The Republic is formed in 1949, when the break with the Commonwealth is made. Vigorous nationalistic movements have also emerged in Scotland, Wales and Brittany, though at differing times.

1922-23 AD
Irish Civil War between pro- and anti-Treaty forces.

1997 AD
September: Scottish people vote 75% in favour of Scottish devolution and restoring the parliament. Welsh people vote 50.3% in favour of limited Welsh devolution and a Welsh Assembly.

1998 AD
May: 71% of Northern Irish and 94% in the Republic of Ireland vote in favour of the Stormont Peace Agreement. Northern Ireland to regain its parliament, the Republic gives up its constitutional claim on the North.