and winters are milder than expected for such a northerly area, although summers are cooler than those in Continental Europe. The earliest evidence of human presence in Ireland is dated at 10,500 BCE (12,500 years ago). The island was Christianised from the 5th century onward.Following the 12th century Norman invasion, England claimed sovereignty.In 2011, the population of Ireland was about 6.6 million, ranking it the second-most populous island in Europe after Great Britain.
By 16,000 BC, rising sea levels due to ice melting caused Ireland to become separated from Great Britain.
These Mesolithic communities lived as hunter-gatherers across the island until about 4000 BC.
The theory holds that there were four separate Celtic invasions of Ireland.
The Priteni were said to be the first, followed by the Belgae from northern Gaul and Britain.
Later, Laighin tribes from Armorica (present-day Brittany) were said to have invaded Ireland and Britain more or less simultaneously.
Lastly, the Milesians (Gaels) were said to have reached Ireland from either northern Iberia or southern Gaul.
How and when the island became Celtic has been debated for close to a century, with the migrations of the Celts being one of the more enduring themes of archaeological and linguistic studies.
Today, there is more than one school of thought on how this occurred.
Alongside mainstream Western culture, a strong indigenous culture exists, as expressed through Gaelic games, Irish music and the Irish language.
The island's culture shares many features with that of Great Britain, including the English language, and sports such as association football, rugby, horse racing, and golf.
is that the Celtic language, Ogham script and culture were brought to Ireland by waves of invading or migrating Celts from mainland Europe.