Celtic tribes arrived on the island from about 600 BC. Invasions by Vikings began in the late 8th century and what is now Dublin was an important Norse trading settlement. The Danes were eventually defeated in 1014. English invasions of the island began in the 12th century.

In the 1600s Ireland came under English Protestant rule, to the disadvantage of the Roman Catholic majority. In 1801 it became part of the United Kingdom.

Wars of independence in the early 20th century led to partition and the creation of the Irish Free State in 1922.  The northern part remained part of the UK.  In 1937 the country drafted a new constitution that confirmed its status as a fully sovereign state.   In 1949 it declared itself a republic, cut all constitutional ties with the UK and ceased to be a member of the British Commonwealth. There was inevitable involvement in the considerable civil unrest beyond its borders in Northern Ireland from the late 1960s to the 1990s.

During British rule and in the early years of independence, Ireland was one of the poorest countries in western Europe. Yet by 2006 it had the eighth highest GDP per capita in the world (on a PPP^†  basis). According to the Economist Intelligence Unit index it then had the highest quality of life in the world (Quality-of-Life report in 2005, pdf, p.4).

^†  purchasing power parity