Early Irish Society was organized into a number of different kingdoms, ruled by kings and clan leaders, with an educated upper class and an artisan class. For many centuries Ireland was ruled under Brehon Law; these laws are amongst the oldest known European laws. The Brehons of ancient Ireland were men of the family who memorized the laws in order to settle disputes among members of the family.
Ireland was Pagan up until around the early fifth century AD. In the 5th century Christian
missionaries began to arrive, including St. Patrick. By around the year 600 Christianity had replaced Paganism. With the coming of Christianity came the written word. Up until that point the Irish had a strong tradition of passing on stories, laws and history through spoken word and memorization. The Book of Kells would have been written sometime around 800 AD.
Ireland has a long history of invasions, beginning with the Vikings around 1100 AD. At first Ireland's villages and monasteries were raided. However, over time the Vikings built settlements in Ireland (Dublin, Limerick, Cork and Wexford). In time the Vikings (the invaders) became assimilated into Irish Society
The Invasion of Norman mercenaries, around 1170, began Norman/English rule over Ireland. These invaders also became assimilated into Irish Society, over time. By the end of the 1500s England had very limited control over Ireland.
During the 1500s English rule became more violent. Henry VIII left the Catholic Church and began the Church of England. Around the same time he declared himself King of Ireland; this would be the beginning of the Catholic and Protestant conflicts between Ireland and England. In 1601 the Irish, with the help of the Spanish, fought against Queen Elizabeth I's army at Kinsale and lost.
The rebellions of 1649 and 1652 were put down by Oliver Cromwell. The Irish suffered great losses. Catholic land was confiscated and divided among Cromwell's soldiers as well as Scottish colonists. Many families were displaced and the legacy of the rebellion. The conflicts between Ireland and England would continue well into the 21st Century.
Penal laws against Catholics were introduced throughout the seventeenth century. These laws excluded Catholics from holding public office, teaching, ownership and inheritance of land, entering certain professions and owning firearms. Catholic clergy were outlawed and for a time Catholics were forced to pay tithes to the Protestant clergy.
In 1798, following a rebellion, the Irish Parliament was abolished. Ireland was now a formal part of the United Kingdom. In 1829 a campaign for the emancipation of Catholics succeeded in removing some of the restrictions that had been placed on Catholics.
From 1845-52 The Great Famine, which was caused by a potato blight destroyed the main food source of the poor. it led to the death, by starvation and disease, of close to a million people. Approximately two million more Irish emigrated over a period of ten years. Ireland's population fell by a quarter. Emigration continued for decades to come. Ireland's population now is roughly the same as it was in the 1870s. Use of the Irish language declined dramatically as Irish speaking areas of Ireland were hit particularly hard by the famine. In recent history an effort has been made to preserve the language, although only a small percentage of the population is fluent in the language.
For Irish Catholics immigration to the United States meant the possibility of steady employment, voting rights and the possibility of owning land. Labor in the US was difficult, but abundant. Immigrants built canals, railroads and worked in factories (the beginnings of assembly line work). Much of the US was built through immigrant labor.
Those Irish who chose to move out of the cities and purchase farms discovered land that was much more conducive to farming and feeding animals than the land in Ireland. Despite the many hardships the Irish faced they saw it as well worth it to come to America. In a letter to the London Times in 1850 one immigrant was quoted as saying, "You must bear in mind that I have purchased the land out, and it is to me and mine an "estate forever", without a landlord . . . you can grow every crop you wish." The US afforded opportunities the United Kingdom did not.
The late 19th century Ireland saw repeated rebellions and calls for land reforms (the land leagues). Laws concerning landowners (English) and tenants (the Irish Catholics) were constantly changing during this time. Tenants had little recourse if rents were raised or if they were evicted. The land leagues of the time often helped tenants to find a new place to live and they keep new tenants from coming into the evicted party's home. This situation, coupled with the famine, would have been a catalyst for decades of Irish emigration. Ireland would not see a free (Southern) Ireland until 1922, gaining full independence in 1931.