The first evidence of human presence in Ireland dates to around 33,000 years ago, with further findings dating the presence of homo sapiens to around 10,500 to 7,000 BC. The receding of the ice after the Younger Dryas cold phase of the Quaternary around 9700 BC, heralds the beginning of Prehistoric Ireland, which includes the archaeological periods known as the Mesolithic, the Neolithic from about 4000 BC and the Copper Age beginning around 2500 BC with the arrival of the Beaker Culture. The Irish Bronze Age proper begins around 2000 BC and ends with the arrival of the Iron Age of the Celtic Hallstatt culture, beginning about 600 BC. The subsequent La Tène culture brought new styles and practices by 300 BC.
Greek and Roman
writers give some information about Ireland during the Classical period (see "protohistoric" period), by which time the island may be termed "Gaelic Ireland". By the late 4th century AD Christianity had begun to gradually subsume or replace the earlier Celtic polytheism. By the end of the 6th century it had introduced writing along with a predominantly monastic Celtic Christian church, profoundly altering Irish society. Viking raids and settlement from the late 8th century AD resulted in extensive cultural interchange, as well as innovation in military and transport technology. Many of Ireland's towns were founded at this time as Viking trading posts and coinage made its first appearance. Viking penetration was limited and concentrated along coasts and rivers, and ceased to be a major threat to Gaelic culture after the Battle of Clontarf in 1014. The Norman invasion in 1169 resulted again in a partial conquest of the island and marked the beginning of more than 800 years of English political and military involvement in Ireland. Initially successful, Norman gains were rolled back over succeeding centuries as a Gaelic resurgence reestablished Gaelic cultural preeminence over most of the country, apart from the walled towns and the area around Dublin known as The Pale.
Reduced to the control of small pockets, the English Crown did not make another attempt to conquer the island until after the end of the Wars of the Roses (1488). This released resources and manpower for overseas expansion, beginning in the early 16th century. However, the nature of Ireland's decentralised political organisation into small territories (known as túatha), martial traditions, difficult terrain and climate and lack of urban infrastructure, meant that attempts to assert Crown authority were slow and expensive. Attempts to impose the new Protestant faith were also successfully resisted by both the Gaelic and Norman-Irish. The new policy fomented the rebellion of the Hiberno-Norman Earl of Kildare Silken Thomas in 1534, keen to defend his traditional autonomy and Catholicism, and marked the beginning of the prolonged Tudor conquest of Ireland lasting from 1534 to 1603. Henry VIII proclaimed himself King of Ireland in 1541 to facilitate the project. Ireland became a potential battleground in the wars between Catholic Counter-Reformation and Protestant Reformation Europe.
England's attempts either to conquer or to assimilate both the Hiberno-Norman lordships and the Gaelic territories into the Kingdom of Ireland provided the impetus for ongoing warfare, notable examples being the 1st Desmond Rebellion, the 2nd Desmond Rebellion and the Nine Years War. This period was marked by the Crown policies of, at first, surrender and regrant, and later, plantation, involving the arrival of thousands of English and Scottish Protestant settlers, and the displacement of both the Hiberno-Normans (or Old English as they were known by then) and the native Catholic landholders. With English colonies going back to the 1550s, Ireland was arguably the first English and then British territory colonised by a group known as the West Country Men. Gaelic Ireland was finally defeated at the battle of Kinsale in 1601 which marked the collapse of the Gaelic system and the beginning of Ireland's history as fully part of the English and later British Empire.
During the 17th century, this division between a Protestant landholding minority and a dispossessed Catholic majority was intensified and conflict between them was to become a recurrent theme in Irish history. Domination of Ireland by the Protestant Ascendancy was reinforced after two periods of religious war, the Irish Confederate Wars in 1641-52 and the Williamite war in 1689–91. Political power thereafter rested almost exclusively in the hands of a minority Protestant Ascendancy, while Catholics and members of dissenting Protestant denominations suffered severe political and economic privations under the Penal Laws.