Ireland's timeline squares with that of the Old Testament. There is a prevailing belief that the Irish are a lost tribe of Israel, but if that is so, there has been very little kosher behavior since they wandered off.
Ireland has many names, Eire is the name of the country on the Republic of Ireland's government-issued postage stamp. “The Emerald Isle” covers about 32,000 sq. mi. including Northern Ireland.
In the 12th century, Ireland was divided into four ecclesiastical provinces: Ulster (northeast), Munster (southwest), Leinster (southeast) and Connaught (northwest). The four provinces were further divided into thirty-two counties. There are currently twenty-six counties in The Republic and six in Northern Ireland. The political separation of the country was finally constituted in 1922, before which the whole island was under English rule for many centuries.
As far as can be verified, the first settlements in Ireland occurred in about 6000 BC. Historically, the first settlement of Ireland occurred around 6000 BC. While there is still much debate as to who those newcomers were, the first recognizable invasion took place when the Gaels, a Celtic-speaking people from western Europe, found their way to the island sometime between about 600 and 150 BC and overwhelmed the previous inhabitants.
During the first century AD the country was organized into five kingdoms, the traditional "Five Fifths of Ireland", and by 400 AD, this had evolved into seven independent kingdoms. These kings were seldom of like mind, but they did on occasion unite in order to make raids on Britain. That is how St. Patrick arrived in Ireland, as a slave who had been captured in an Irish raid.
The Vikings were very hard on Ireland in the 9th and 10th centuries, with their ferocious attacks on the monasteries and churches of Ireland; there were great atrocities. In the middle of the ninth century, the Danes invaded the island and were followed by Danish settlers who gradually assimilated with the local population and adopted Christianity.
When the four ecclesiastical provinces were created in 1152, both Gaelic and Danish elements of the population helped form a united church. This reform, and others advocated by the Irish church were not well received by the pope, Adrian IV, an Englishman. In 1155 he conferred on Henry II of England the lordship of Ireland hoping to cure some of Ireland's religious ills. In 1168 the English invaded and soon thereafter began invoking reforms, many dealing with the granting of land, invoking havoc on the traditional political and social structure of the society.
From the end of the twelfth century to about 1400, many Normans from England moved to Ireland and settled the eastern areas, particularly around Dublin. Some assimilated but strife continued between the native Irish and the colonists.